Journal articles: 'STMP crosslinking'

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Surini, Silvia, Lusiana Ariani, Kurnia Ss Putri, Hayun Hayun, and Effionora Anwar. "COPROCESSED EXCIPIENTS OF CROSSLINKED AMYLOSE AND XANTHAN GUM FOR USE IN CONTROLLED RELEASE DOSAGE FORMS." International Journal of Applied Pharmaceutics 10, no. 1 (December 20, 2018): 59. http://dx.doi.org/10.22159/ijap.2018.v10s1.13.

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Objective: This study was aimed to obtain a new excipient that can be used as a polymer matrix for the formulation of controlled release dosage forms.Methods: This study used coprocessing and crosslinking methods on amylose and xanthan gum (XG) to obtain a new excipient that can be usedfor controlled release matrix of pharmaceutical dosage forms. The coprocessing step was conducted by drum drying, and the crosslinking step wasprepared using 6 and 12% sodium trimetaphosphate (STMP). The produced novel excipients were characterized in terms of infrared (IR) spectrum,substitution degree, moisture content, swelling index, and gel strength.Results: Our results showed that amylose–XG excipients crosslinked using 6% STMP have greater gel strength and better swelling indexes thanexcipients crosslinked using 12% STMP. All coprocessed excipients exhibited no differences in their IR spectra, whereas the crosslinked excipientsdid, indicating a structural change due to the addition of phosphate groups. Crosslinking amylose–xanthan-coprocessed excipients using 6% STMPproduced degrees of substitution (DSs) of 7–8 phosphates per 100 monomeric subunits. The excipients had a moisture content of 8.21–12.85%, andthe pH of a 1% solution of excipients was 6.21–6.43. In addition, the swelling index and gel strength of the excipient where both amylose and XG werecrosslinked together Were more than 1 where only amylose was crosslinked.Conclusion: The crosslinking amylose–xanthan-coprocessed excipient using 6% STMP is more suitable for use in controlled release dosage forms,particularly when the polymer ratio is 1:1.

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Wang, Hongxia, Yu Liao, Ailiang Wu, Bing Li, Jun Qian, and Fuyuan Ding. "Effect of Sodium Trimetaphosphate on Chitosan-Methylcellulose Composite Films: Physicochemical Properties and Food Packaging Application." Polymers 11, no. 2 (February 20, 2019): 368. http://dx.doi.org/10.3390/polym11020368.

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Environmentally friendly food packaging currently attracts much interest. Sodium trimetaphosphate (STMP) finds specialized applications in food, but it is rarely used as a crosslinking agent. In this study, STMP was used as a crosslinking agent to prepare chitosan/methylcellulose composite films. Both antibacterial and physicochemical properties of the composite film were improved by crosslinking with STMP. The crosslinked films, with good antibacterial activity (~99%), had increased tensile strength, a higher elongation at break, a lower swelling ratio and solubility, and a lower enzymatic degradation than the non-crosslinked films. Furthermore, the crosslinked films showed an excellent preservative effect on fresh-cut wax gourd after three days at room temperature. The obtained films crosslinked by STMP can be potentially applied to the food industry, such as food functional packaging, providing a novel alternative to traditional plastic packages.

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Racksanti, Anucha, Sorapong Janhom, Sittiporn Punyanitya, Ruangsri Watanesk, and Surasak Watanesk. "Crosslinking Density of Silk Fibroin – Rice Starch Hydrogels Modified with Trisodium Trimetaphosphate." Applied Mechanics and Materials 446-447 (November 2013): 366–72. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.366.

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Silk fibroin (SF) and rice starch (RS) are both biopolymers being non-toxic, biocompatible and biodegradable which can be utilized as hydrogels. The aim of this study was to prepare the SF–RS hydrogels modified with trisodium trimetaphosphate (STMP) and determine its crosslinking density for providing a guideline for preparing better quality absorbable hydrogels. The SF–RS hydrogels modified with various percentages of STMP were prepared by solution casting at pH 12 then neutralized to pH 7. The functional groups and molecular linkages of the hydrogels were investigated by Fourier transform infrared spectrometry (FTIR) and proton nuclear magnetic resonance (1H NMR) spectrometry, respectively. Finally, the crosslinking density of the hydrogels was determined by UV/Vis spectrophotometry via the measurement of the relative amount of methylene blue (RMB) bound to the hydrogels. Results from the FTIR and 1H NMR spectra revealed that linkages within the hydrogels occurred mainly between the O–H groups of RS and the triphosphate groups of STMP. From the MB adsorption study, the crosslinking density of the SF–RS hydrogel with 1.0 %w/w STMP at the 60 min saturation time was approximately 63 %.

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Samoila, Iuliana, Sorina Dinescu, Gratiela Gradisteanu Pircalabioru, Luminita Marutescu, Gheorghe Fundueanu, Magdalena Aflori, and Marieta Constantin. "Pullulan/Poly(Vinyl Alcohol) Composite Hydrogels for Adipose Tissue Engineering." Materials 12, no. 19 (October 1, 2019): 3220. http://dx.doi.org/10.3390/ma12193220.

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Composite hydrogels based on pullulan (HP) and poly(vinyl alcohol) (PVA) were both prepared by simple chemical crosslinking with sodium trimethaphosphate (STMP) or by dual crosslinking (simultaneously chemical crosslinking with STMP and physical crosslinking by freeze-thaw technique). The resulting hydrogels and cryogels were designed for tissue engineering applications. PVA, with two different molecular weights (47,000 and 125,000 g/mol; PVA47 and PVA125, respectively), as well as different P/PVA weight ratios were tested. The physico-chemical characterization of the hydrogels was performed by FTIR spectroscopy and scanning electron microscopy (SEM). The swelling kinetics, dissolution behavior, and degradation profiles in simulated physiological conditions (phosphate buffer at pH 7.4) were investigated. Pullulan concentration and the crosslinking method had significant effects on the pore size, swelling ratio, and degradation profiles. Cryogels exhibit lower swelling capacities than the conventional hydrogels but have better stability against hydrolitic degradation. Biocompatibility of the hydrogels was also investigated by both MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and LDH (lactaten dehydrogenase) assay. The MTT and LDH assays proved that dual crosslinked HP/PVA125 (75:25, w/w) scaffolds are more biocompatible and promote to a greater extent the adhesion and proliferation of L929 murine fibroblast cells than chemically crosslinked HP/PVA47 (50/50, w/w) scaffolds. Moreover, the HP/PVA125 cryogel had the best ability for the adipogenic differentiation of cells. The overall results demonstrated that the HP/PVA composite hydrogels or cryogels are suitable biomaterials for tissue engineering applications.

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Zhu, Wei, Jin Gao, Xiao Gang Li, Jun Li Lin, Han Hui Cao, and Bai Tian Sun. "Mechanical Characteristics of PVA/STMP Hydrogel in Tensile and Unconfined Compression." Applied Mechanics and Materials 157-158 (February 2012): 1372–75. http://dx.doi.org/10.4028/www.scientific.net/amm.157-158.1372.

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Hydrogels based on Poly(vinyl alcohol) (PVA) were synthesized using the combining method of chemical agent and freezing-thawing cycle. Sodium Trimetaphosphate (STMP) is a kind of crosslinking agent in this reaction. The resulting hydrogels were characterized in terms of tensile properties and compression stress-strain testing. The influences of STMP and water content on mechanical properties of hydrogels were investigated. It is suggested that PVA hydrogel has excellent tensile strength, higher elongation at break and viscoelastic materials’ stress-strain curve. Tensile strength of specimens without STMP increases from 4 to 6.8 MPa, as well as elongation increase from 300% to 458%, respectively. When the strain changes from 10% to 50%, tangent compressive modulus dramatically increases from 0.58 to 9.9 MPa for hydrogels with 80wt % water and 0.41 to 5.4 MPa for 85wt % water. Meanwhile, the addition of STMP can further improve the mechanical properties of PVA hydrogel.

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Dulong, Virginie, Renauld Forbice, Eric Condamine, Didier Le Cerf, and Luc Picton. "Pullulan–STMP hydrogels: a way to correlate crosslinking mechanism, structure and physicochemical properties." Polymer Bulletin 67, no. 3 (January 20, 2011): 455–66. http://dx.doi.org/10.1007/s00289-010-0435-2.

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Maulani, Rijanti Rahaju, Asep Hidayat, and Ujang Dinar Husyari. "Effect of dual chemically modified on functional properties of white corn starch." Asia Proceedings of Social Sciences 2, no. 1 (December 2, 2018): 77–80. http://dx.doi.org/10.31580/apss.v2i1.430.

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The purpose of the research was to study functional properties of dual-modified two varieties of white corn starch, namely Anoman and Pulut. Modifications of white corn starch used two treatment factors, namely hydroxypropylation reaction at two levels of propylene oxide concentration (8% and 10%) followed by crosslinking reactions on two combinations of STMP phosphate compounds and STPP (ratio 1%:4% and 2%:5%). The results showed that the dual modification can improve the functional properties of white corn starch Anoman dan Pulut variety compared with its native. The dual modified white corn starches of Anoman variety significantly different with Anoman variety on the characteristic of pasting properties, water absorption capacity, swelling volume, clarity of paste, and freeze thaw stability.

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Rosendo-González, Verónica, Javier Illescas, María del Carmen Díaz-Nava, Yolanda Alvarado-Pérez, and José Juan García-Sánchez. "Synthesis and characterization of clay nanocomposites based on starch." MRS Advances 4, no. 59-60 (2019): 3243–49. http://dx.doi.org/10.1557/adv.2019.403.

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ABSTRACTIn this work, the synthesis of starch-clay nanocomposites was carried out. For this purpose, natural starch was extracted from rice grains and it was characterized by structural and spectrophotometric techniques. Afterwards, it was used as the polymer matrix for the synthesis of nanocomposites crosslinked with different agents: glycerol, citric acid (CA) and sodium trimetaphosphate (STMP). As a reinforcement phase, a natural Mexican clay from the Montmorillonite-type (Mt), was employed, which was modified with a cationic surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), in order to exchange cations, present in the interlaminar spaces of the raw clay mineral with those of the cationic surfactant; thus, changing its nature from hydrophilic to hydrophobic. Characterization, of both natural and organo-modified clays, was carried out by means of scanning electron microscopy (SEM), to determine the change in morphology between these two minerals; X-ray diffraction analysis (XRD), to obtain the crystalline structure of the organo-modified clay and that of the raw clay mineral (Mt). Also, the Fourier transform infrared spectroscopy (FTIR) was employed to determine materials spectra, and their thermal stability was evaluated by means of the thermogravimetric analysis (TGA). On the other hand, the synthesis of these nanocomposites was performed using different crosslinking agents, glycerol, CA or STMP, in order to identify the effect of them into the final properties of these materials.

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Zhao, Yuelong, Hui Sun, Biao Yang, Baomin Fan, Huijuan Zhang, and Yunxuan Weng. "Enhancement of Mechanical and Barrier Property of Hemicellulose Film via Crosslinking with Sodium Trimetaphosphate." Polymers 13, no. 6 (March 17, 2021): 927. http://dx.doi.org/10.3390/polym13060927.

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Hemicellulose is a kind of biopolymer with abundant resources and excellent biodegradability. Owing to its large number of polar hydroxyls, hemicellulose has a good barrier performance to nonpolar oxygen, making this biopolymer promising as food packaging material. Hydrophilic hydroxyls also make the polymer prone to water absorption, resulting in less satisfied strength especially under humid conditions. Thus, preparation of hemicellulose film with enhanced oxygen and water vapor barrier ability, as well as mechanical strength is still sought after. Herein, sodium trimetaphosphate (STMP) was used as esterification agent to form a crosslinked structure with hemicellulose through esterification reaction to render improved barrier performance by reducing the distance between molecular chains. The thus modified hemicellulose film achieved an oxygen permeability and water vapor permeability of 3.72 cm3 × μm × m−2 × d−1 × kPa−1 and 2.85 × 10−10 × g × m−1 × s−1 × Pa−1, respectively, at the lowest esterification agent addition of 10%. The crosslinked structure also brought good mechanical and thermal properties, with the tensile strength reaching 30 MPa, which is 118% higher than that of the hemicellulose film. Preliminary test of its application in apple preservation showed that the barrier film obtained can effectively slow down the oxidation and dehydration of apples, showing the prospect of application in the field of food packaging.

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Leone, Gemma, Marco Consumi, Simone Pepi, Alessio Pardini, Claudia Bonechi, Gabriella Tamasi, Alessandro Donati, Claudio Rossi, and Agnese Magnani. "Poly-vinyl alcohol (PVA) crosslinked by trisodium trimetaphosphate (STMP) and sodium hexametaphosphate (SHMP): Effect of molecular weight, pH and phosphorylating agent on length of spacing arms, crosslinking density and water interaction." Journal of Molecular Structure 1202 (February 2020): 127264. http://dx.doi.org/10.1016/j.molstruc.2019.127264.

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Mallek, Hichem, Corinne Jegat, Nathalie Mignard, Mohamed Taha, Majdi Abid, and Souhir Abid. "One-step Synthesis of PCL-Urethane Networks using a Crosslinking/de-crosslinking Agent." Journal of Macromolecular Science, Part A 50, no. 7 (July 3, 2013): 728–37. http://dx.doi.org/10.1080/10601325.2013.792218.

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Chiaradia, Viviane, Saltuk B. Hanay, Scott D. Kimmins, Débora de Oliveira, Pedro H. H. Araújo, Claudia Sayer, and Andreas Heise. "Crosslinking of Electrospun Fibres from Unsaturated Polyesters by Bis-Triazolinediones (TAD)." Polymers 11, no. 11 (November 4, 2019): 1808. http://dx.doi.org/10.3390/polym11111808.

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Crosslinking of an unsaturated aliphatic polyester poly(globalide) (PGl) by bistriazolinediones (bisTADs) is reported. First, a monofunctional model compound, phenyl–TAD (PTAD), was tested for PGl functionalisation. 1H-NMR showed that PTAD–ene reaction was highly efficient with conversions up to 97%. Subsequently, hexamethylene bisTAD (HM–bisTAD) and methylene diphenyl bisTAD (MDP–bisTAD) were used to crosslink electrospun PGl fibres via one- and two-step approaches. In the one-step approach, PGl fibres were collected in a bisTAD solution for in situ crosslinking, which resulted in incomplete crosslinking. In the two-step approach, a light crosslinking of fibres was first achieved in a PGl non-solvent. Subsequent incubation in a fibre swelling bisTAD solution resulted in fully amorphous crosslinked fibres. SEM analysis revealed that the fibres’ morphology was uncompromised by the crosslinking. A significant increase of tensile strength from 0.3 ± 0.08 MPa to 2.7 ± 0.8 MPa and 3.9 ± 0.5 MPa was observed when PGI fibres were crosslinked by HM–bisTAD and MDP–bisTAD, respectively. The reported methodology allows the design of electrospun fibres from biocompatible polyesters and the modulation of their mechanical and thermal properties. It also opens future opportunities for drug delivery applications by selected drug loading.

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Dong, Yishi, Peixi Wang, Ting Wei, Tao Zhou, Mengge Huangfu, and Zhaoqiang Wu. "Smart Antibacterial Surfaces Established by One-Step Photo-Crosslinking." Advanced Materials Interfaces 4, no. 24 (October 31, 2017): 1700953. http://dx.doi.org/10.1002/admi.201700953.

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Ehrmann, Andrea. "Non-Toxic Crosslinking of Electrospun Gelatin Nanofibers for Tissue Engineering and Biomedicine—A Review." Polymers 13, no. 12 (June 15, 2021): 1973. http://dx.doi.org/10.3390/polym13121973.

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Electrospinning can be used to prepare nanofiber mats from diverse polymers, polymer blends, or polymers doped with other materials. Amongst this broad range of usable materials, biopolymers play an important role in biotechnological, biomedical, and other applications. However, several of them are water-soluble, necessitating a crosslinking step after electrospinning. While crosslinking with glutaraldehyde or other toxic chemicals is regularly reported in the literature, here, we concentrate on methods applying non-toxic or low-toxic chemicals, and enzymatic as well as physical methods. Making gelatin nanofibers non-water soluble by electrospinning them from a blend with non-water soluble polymers is another method described here. These possibilities are described together with the resulting physical properties, such as swelling behavior, mechanical strength, nanofiber morphology, or cell growth and proliferation on the crosslinked nanofiber mats. For most of these non-toxic crosslinking methods, the degree of crosslinking was found to be lower than for crosslinking with glutaraldehyde and other common toxic chemicals.

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Yao, Hongyan, Na Zhang, Ningning Song, Kunzhi Shen, Pengfei Huo, Shiyang Zhu, Yunhe Zhang, and Shaowei Guan. "Microporous polyimide networks constructed through a two-step polymerization approach, and their carbon dioxide adsorption performance." Polymer Chemistry 8, no. 8 (2017): 1298–305. http://dx.doi.org/10.1039/c6py01814a.

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Jang, Jeongmin, Hyejin Park, Haemin Jeong, Eunbi Mo, Yongbin Kim, Jeong Suk Yuk, Siyoung Q. Choi, Young-Wun Kim, and Jihoon Shin. "Thermoset elastomers covalently crosslinked by hard nanodomains of triblock copolymers derived from carvomenthide and lactide: tunable strength and hydrolytic degradability." Polymer Chemistry 10, no. 10 (2019): 1245–57. http://dx.doi.org/10.1039/c8py01765d.

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Lin, Huirong, Shuang Li, Junqing Wang, Chengchao Chu, Yang Zhang, Xin Pang, Peng Lv, et al. "A single-step multi-level supramolecular system for cancer sonotheranostics." Nanoscale Horizons 4, no. 1 (2019): 190–95. http://dx.doi.org/10.1039/c8nh00276b.

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A multi-level supramolecular system produced by single-step Fe³⁺-mediated ionic crosslinking self-assembly can overcome the critical issues of current sonodynamic therapy (SDT) and address the need to monitor therapeutic effects in vivo with a non-invasive approach.

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Higham, Alina K., Christopher A. Bonino, Srinivasa R. Raghavan, and Saad A. Khan. "Photo-activated ionic gelation of alginate hydrogel: real-time rheological monitoring of the two-step crosslinking mechanism." Soft Matter 10, no. 27 (2014): 4990–5002. http://dx.doi.org/10.1039/c4sm00411f.

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Cheng, Qiuli, Xiaowei Guo, Jiawei Zou, Xiaoyu Shi, Shuxiang Ding, Zuosen Shi, Song Zhu, and Zhanchen Cui. "A photo-crosslinked hybrid interpenetrating polymer network (IPN) for antibacterial coatings on denture base materials." New Journal of Chemistry 43, no. 42 (2019): 16647–55. http://dx.doi.org/10.1039/c9nj02609f.

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Wu, Bozhen, Liming Shi, Qi Zhang, and Wen-Jun Wang. "Microencapsulation of 1-hexadecanol as a phase change material with reversible thermochromic properties." RSC Advances 7, no. 67 (2017): 42129–37. http://dx.doi.org/10.1039/c7ra06764j.

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Kaltenegger-Uray, Rieß, Lucyshyn, Holzer, and Kern. "Physical Foaming and Crosslinking of Polyethylene with Modified Talcum." Polymers 11, no. 9 (September 9, 2019): 1472. http://dx.doi.org/10.3390/polym11091472.

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The aim of this study was the investigation of the use of modified talcum for supporting crosslinking and as novel nucleating agent for physical foaming of polyethylene. For the modification of the talcum, a thermal initiator was linked to the talcum surface. During the extrusion process, the initiator decomposes, and gas and radicals are formed. The gas generates the nucleation of cells and the radicals support the crosslinking process between the polymer chains. The modification of the talcum was performed in three steps: The first step was the grafting of alkoxysilanes onto the talcum surface. The second step was the chlorination of the thermal initiator for an easier linkage, and the last step was the linking between the initiator and the silanes grafted onto the talcum surface. For this study, two investigations were carried out. One investigation was the analysis of the crosslinking effect with the modified talcum. For this purpose, polyethylene plates were compression molded and the viscoelastic properties were measured with a parallel plate rheometer. The use of the modified talcum led to a higher crosslinking density. The second investigation was the physical foaming experiment in an extrusion process with nitrogen as blowing agent using both a pure and the modified talcum as nucleating agents. The foamed samples were characterized in terms of density, cell size and cell density, and compared with each other. The blend with the modified nucleating agent indicated a foam structure with a smaller mean cell size and a lower density compared to the use of the pristine nucleating agent.

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Li, Qian Yue, Jun Xu, Wen Zheng Zhang, and Peng Li. "Preparation and Characterization of Chiral Cyclosiloxane-Based Liquid-Crystalline Elastomers Bearing Menthyl Groups." Advanced Materials Research 466-467 (February 2012): 445–48. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.445.

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Chiral side-chain liquid-crystalline elastomers (LCEs) IP~IVP containig menthyl groups were synthesized by a one-step hydrosilylation reaction. The chemical structures and LC properties of the monomers and polymers were characterized by use of various experimental techniques. The effect of crosslinking mesogens on mesomorphic properties of the chiral LCEs was studied by swelling experiments. All the samples IP~IVP showed cholesteric mesophase when they were heated and cooled, proved by visual observation and X-ray measurements. The glass transition temperature (Tg) of elastomers increased slightly with increase of crosslinking mesogens in the polymer systems, but mesophase-isotropic phase transition temperature (Ti) decreased slightly, suggesting that the temperature range of mesophase became narrow with increase of crosslinking mesogens for all the elastomers. The maximum reflection bands shift slightly to long wavelength and become broad at the same temperature, indicating that the helical structure is partially disrupted because of both the constraint of chemical crosslinking agents and the different mesogenic units.

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Xu, Xingguang, Bobby Pejcic, Charles Heath, and Colin D. Wood. "Carbon capture with polyethylenimine hydrogel beads (PEI HBs)." Journal of Materials Chemistry A 6, no. 43 (2018): 21468–74. http://dx.doi.org/10.1039/c8ta07760f.

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Rynkowska, Fatyeyeva, Marais, Kujawa, and Kujawski. "Chemically and Thermally Crosslinked PVA-Based Membranes: Effect on Swelling and Transport Behavior." Polymers 11, no. 11 (November 1, 2019): 1799. http://dx.doi.org/10.3390/polym11111799.

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The novel poly(vinyl alcohol) (PVA)-based membranes were prepared using the two-step crosslinking approach: the chemical crosslinking of PVA using sulfosuccinic acid (SSA) (0–50 wt.%) and the thermal treatment (120–160 °C). The membrane composition and crosslinking temperature were optimized in terms of the mechanical and transport properties. The FTIR-ATR analysis revealed that the increase of the SSA concentration and crosslinking temperature resulted in the rise of the ester bond bands intensity due to the esterification reaction between PVA and SSA. As a consequence, the PVA-based membrane with 50 wt % SSA and crosslinked at 140 °C showed the reduced Young’s modulus (from 1266.2 MPa to 1.4 MPa) and elongation at break (from 316% to 66%) in comparison with the pure PVA membrane. The studied swelling behavior of the obtained membranes revealed significantly higher water sorption than that in methanol and propal-2-ol whatever the crosslinking temperature. The performed studies provide a new way of tailoring the membrane physicochemical properties, in particular, the surface hydrophilicity. In addition, the obtained results are crucial for the design and elaboration of the polymer membranes for the pervaporative separation of the liquid-liquid mixtures, in particular, for the alcohol dehydration.

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Luo, Zu Tie, and He Ping Li. "Synthesis and Characterization of Crosslinking Etherification Bagasse Xylan." Advanced Materials Research 960-961 (June 2014): 204–7. http://dx.doi.org/10.4028/www.scientific.net/amr.960-961.204.

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The bagasse xylan is a polysaccharide that occurs in nature in enormous amount in various one year-and perennial plants. Versatile ways to generate bio-based functional polymers result from the chemical modification of this biopolymer. The crosslinking etherification bagasse xylan (CEBX) has been synthesized by using aqueous solution polymerization method. It implies the use of sodium hydroxide, chloroacetic acid as a carboxymethylating agent and epichlorohydrin as crosslinking agent. The DS values of Carboxymethylated xylan up to 0.59 can be controlled by adjusting the molar ratio in a two step syntheses. Crosslinking etherification bagasse xylan are water soluble at a DS of 0.3. The result showed that the final product had excellent surface activity. IR spectrometry were applied to characterize the carboxymethyl xylans in detail, and revealed characteristic absorption peaks at 1600, 1426 and 1324cm−1.

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Ye, Yumin, Qing Song, and Yu Mao. "Single-step fabrication of non-leaching antibacterial surfaces using vapor crosslinking." J. Mater. Chem. 21, no. 1 (2011): 257–62. http://dx.doi.org/10.1039/c0jm02578j.

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Jia, Ying Gang, Kun Ming Song, and Bao Yan Zhang. "Synthesis and Phase Behavior of Polysiloxane Nematic Liquid Crystal Elastomers." Advanced Materials Research 535-537 (June 2012): 1185–88. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1185.

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This paper describes the synthesis of new side chain nematic liquid crystalline elastomers (LCEs) by a one-step hydrosilication reaction. The phase behavior and mesomorphism were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction (XRD). The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers P1 – P8 was discussed. The nematic LCEs exhibit elasticity, reversible phase transitions, and nematic thread texture. The experimental results demonstrate that the glass transition temperature and isotropic temperature of nematic LCEs decreased with increasing the content of crosslinking unit.

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Sangregorio, Guigo, Jong, and Sbirrazzuoli. "Kinetics and Chemorheological Analysis of Cross-Linking Reactions in Humins." Polymers 11, no. 11 (November 2, 2019): 1804. http://dx.doi.org/10.3390/polym11111804.

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Humins is a biomass-derived material, co-product of the acid-catalyzed conversion of cellulose and hemicellulose to platform chemicals. This work presents a thorough study concerning the crosslinking kinetics of humins by chemorheological analysis and model-free kinetics under isothermal and non-isothermal curing. Humins can auto-crosslink under the effect of temperature, and the reaction can be fastener when adding an acidic initiator. Thus, the effect of P-Toluenesulfonic acid monohydrate (pTSA) on the crosslinking kinetics was also studied. The dependencies of the effective activation energy (Eα-dependencies) were determined by an advanced isoconversional method and correlated with the variation of complex viscosity during curing. It is shown that humins curing involves multi-step complex reactions and that the use of an acidic initiator allows faster crosslinking at lower temperatures, involving lower Eα. The shift from chemical to diffusion control was also estimated.

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Khouri, Joseph, Alexander Penlidis, and Christine Moresoli. "Viscoelastic Properties of Crosslinked Chitosan Films." Processes 7, no. 3 (March 14, 2019): 157. http://dx.doi.org/10.3390/pr7030157.

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Chitosan films containing citric acid were prepared using a multi-step process called heterogeneous crosslinking. These films were neutralized first, followed by citric acid addition, and then heat treated at 150 °C/0.5 h in order to potentially induce covalent crosslinking. The viscoelastic storage modulus, E′, and tanδ were studied using dynamic mechanical analysis, and compared with neat and neutralized films to elucidate possible crosslinking with citric acid. Films were also prepared with various concentrations of a model crosslinker, glutaraldehyde, both homogeneously and heterogeneously. Based on comparisons of neutralized films with films containing citric acid, and between citric acid films either heat treated or not heat treated, it appeared that the interaction between chitosan and citric acid remained ionic without covalent bond formation. No strong evidence of a glass transition from the tanδ plots was observable, with the possible exception of heterogeneously crosslinked glutaraldehyde films at temperatures above 200 °C.

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Duong, Hien T. T., T. L. Uyen Nguyen, Josef Kumpfmüller, and Martina H. Stenzel. "Synthesis of Core - Shell Nanoparticles with Polystyrene Core and PEO Corona from Core-Crosslinked Micelles by the RAFT Process." Australian Journal of Chemistry 63, no. 8 (2010): 1210. http://dx.doi.org/10.1071/ch10127.

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Core–shell nanoparticles have been synthesized by core crosslinking of micelles. The underlying block copolymer, poly(oligo(ethylene glycol methyl ether methacrylate))-block-polystyrene (POEGMA-b-PS), was synthesized successfully by the reversible addition–fragmentation chain transfer (RAFT) process, using POEGMA as a macro-RAFT agent. The block copolymers were self-assembled into micelles in aqueous media and the resulting micelles and the RAFT endgroup, located in the core of the micelle, were used for the subsequent crosslinking step using a crosslinker, divinyl benzene (DVB). The rate of the crosslinking reaction was found to be slow with less than 20% conversion being achieved after 72 h. Nevertheless, crosslinked micelles were obtained and only a small fraction of free block copolymers remained. Cytotoxicity tests confirmed the biocompatibility of the prepared core-crosslinked micelles. In addition the crosslinked micelles were taken up by L929 cells without causing any signs of cell damage.

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Jiang, Ying, Yuehua Cong, and Baoyan Zhang. "Synthesis and characterization of chiral smectic side-chain liquid crystalline elastomers containing nematic and chiral mesogens." New Journal of Chemistry 40, no. 11 (2016): 9352–60. http://dx.doi.org/10.1039/c6nj02001a.

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A novel series of siloxane-based chiral smectic side-chain liquid crystalline elastomers containing nematic and chiral mesogens were fabricated through synthesis involving a one-step hydrosilication reaction via a liquid crystalline crosslinking agent containing smectic and nematic phases.

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Pergal, Marija, Jasna Dzunuzovic, Sanja Ostojic, Miodrag Pergal, Aleksandra Radulovic, and Slobodan Jovanovic. "Poly(urethane-siloxane)s based on hyperbranched polyester as crosslinking agent: Synthesis and characterization." Journal of the Serbian Chemical Society 77, no. 7 (2012): 919–35. http://dx.doi.org/10.2298/jsc111013006p.

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A series of novel polyurethane crosslinked structures (PUs) was prepared from ?,?-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4?-methylenediphenyl diisocyanate and Boltorn? hyperbranched polyester of the third pseudo generation. The hydroxyfunctional hyperbranched aliphatic polyester with 26 end groups was used as crosslinking agent. In order to improve the compatibility of all reactants during the synthesis, PU samples were prepared by a step-growth polymerization in two stages in solution. The soft EO-PDMS-EO segment content was varied in the range from 15 to 40 wt.%. The influence of the EO-PDMS-EO content on the swelling behavior, crosslinking density, hardness, thermal and surface properties of the synthesized PUs was investigated. The structure of the synthesized polyurethanes was confirmed by the presence of specific bands in Fourier transform infrared spectra. Swelling studies were carried out to determine the crosslinking density and polyurethane networks with lower EOPDMS- EO content revealed higher crosslinking density. The glass transition temperature of the synthesized PUs, determined by differential scanning calorimetry, slightly increased from 50 to 58?C by decreasing EO-PDMS-EO content as a consequence of higher crosslinking density of samples. The increase of EO-PDMS-EO content leads to the better thermal stability, as it was confirmed by the value of the starting temperature of thermal degradation. The surface of the polyurethane networks became more hydrophobic with increasing EO-PDMS-EO content. The surface morphology of synthesized polyurethanes was analyzed by scanning electron microscopy.

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Al-Jwaid, Areej K., Dmitriy Berillo, Irina N. Savina, Andrew B. Cundy, and Jonathan L. Caplin. "One-step formation of three-dimensional macroporous bacterial sponges as a novel approach for the preparation of bioreactors for bioremediation and green treatment of water." RSC Advances 8, no. 54 (2018): 30813–24. http://dx.doi.org/10.1039/c8ra04219e.

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Clemetson, Kenneth J. "Snake Venom and Receptor Crosslinking." Blood 114, no. 22 (November 20, 2009): SCI—37—SCI—37. http://dx.doi.org/10.1182/blood.v114.22.sci-37.sci-37.

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Abstract Abstract SCI-37 Nearly all poisonous snakes venoms contain proteins including snaclecs (snake C-type lectins) and metalloproteases, which influence haemostasis by interacting with coagulation factors or platelets. Like other venom constituents they weaken the prey and make it easier to swallow and digest. Although some of those that affect platelets inhibit receptors, particularly integrins, many activate platelets by clustering receptors. The main receptors involved are GPIb and GPVI and the snaclecs and metalloproteases activate platelets in the same way as their natural ligands, von Willebrand factor (VWF) and collagen. Both VWF and collagen are thought to activate platelets by clustering receptors acting in somewhat parallel ways. In both cases a mainly signalling receptor, GPIb or GPVI, respectively, is clustered to activate an integrin, aIIbb3 or a1b2, respectively. The first step can be simulated by agents that bind to and cross-link GPIb or GPVI. These include antibodies, synthetic peptides or snake venom proteins. Many of the activating snaclecs belong to the tetrameric heterodimer group such as flavocetin, convulxin and its homologues, and some use both receptors. There remain however many unanswered questions about the non-covalent structure of these molecules and how they interact with receptors on, possibly, more than one platelet to induce activation even at very low concentrations (pM). A second class of snaclecs, including aggretin (rhodocytin), which has CLEC-2 as receptor, and purpureotin that acts via GPIb, are non-covalent dimers of heterodimers but may reorganise to form higher non-covalent multimers. These non-covalent interactions are still poorly understood and may be responsible for the low activity of recombinant snaclecs. Several activating snaclecs are glycosylated. Although this may simply enhance solubility, interactions with prey molecules can not yet be excluded. Many simple heterodimeric snaclecs are superficially inhibitory of washed platelets but can be converted to activators by cross-linking, either naturally or artificially. Finally, a major problem in snake venom genomics is ascribing function, such as target molecules, to novel snaclecs identified by DNA sequence alone. Although modelling has made great progress there are still too many unknown factors. Disclosures No relevant conflicts of interest to declare.

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Li, Lei, Aijuan Zhang, Jianhui Yu, Wenqing Li, Hui Gao, Ke Tian, and Hua Bai. "One-step preparation of hierarchically porous polyureas: Simultaneous foaming and hyper-crosslinking." Polymer 108 (January 2017): 332–38. http://dx.doi.org/10.1016/j.polymer.2016.11.002.

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Umaningrum, Dewi, Uripto Trisno Santoso, Radna Nurmasari, and Rahmat Yunus. "ADSORPTION KINETICS OF Pb(II), Cd(II) AND Cr(III) ON ADSORBENT PRODUCED BY PROTECTED-CROSSLINKING OF HUMIC ACID-CHITOSAN." Indonesian Journal of Chemistry 10, no. 1 (June 21, 2010): 80–87. http://dx.doi.org/10.22146/ijc.21484.

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Study on adsorption kinetics of of Pb(II), Cd(II) and Cr(III) on adsorbent which was produced by protected-crosslinking of humic acid-chitosan has been done. The Langmuir-Hinshelwood, pseudo first- and second-order kinetics models were used to describe the kinetic data, and the rate constants of adsorption were also evaluated. The experimental data fitted well the second-order kinetics model, indicating that the chemical sorption is the rate-limiting step, instead of mass transfer. The initial metal ion concentration significantly affects the adsorption rate. An increase in initial metal ion concentration results in the decrease in adsorption rate of the metals. Keywords: kinetics, adsorption, crosslinking, humic acid, chitosan

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Slusarewicz, Paul, Keng Zhu, and Tom Hedman. "Kinetic Analysis of Genipin Degradation in Aqueous Solution." Natural Product Communications 5, no. 12 (December 2010): 1934578X1000501. http://dx.doi.org/10.1177/1934578x1000501202.

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Degradation of genipin (GP), a low toxicity natural protein crosslinking agent, in aqueous solution was monitored by HPLC at various pH levels. Degradation of GP was consistent with a mechanism consisting of a first order reaction with a reversible first step. Formation of the intermediate was slowest at more neutral pHs while formation of the irreversible product was correlated to increasing alkalinity. Degradation at all pHs was enhanced by the presence of phosphate ions. Degradation of GP most likely proceeds via the reversible opening of the dihydropyran ring by water followed by irreversible polymerization of the intermediate. Degraded solutions containing no detectable GP or intermediate, however, are still capable of crosslinking proteins.

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Muller, R., M. Bouquey, F. Mauguière, G. Schlatter, C. Serra, and J. Terrisse. "Rheology of Reactive Polymer Blends: Separation of Mixing and Reatcion Steps." Applied Rheology 11, no. 3 (June 1, 2001): 141–52. http://dx.doi.org/10.1515/arh-2001-0009.

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Abstract The crosslinking reaction in various types of polymer blends was followed by rheological measurements. Miscible polymers with controlled glass transition temperature, chain length and number of functional units per chain were synthesized by bulk radical copolymerization. Other experiments were carried out on immiscible systems based on commercial polymers. Blends were either prepared in a batch mixer or directly in the parallel-plate geometry of a rotational rheometer. Due to the low glass transition or melting temperature of most blend components, it was usually possible to separate the mixing step which was carried out at low temperature from the crosslinking reaction which was followed by small amplitude dynamic measurements at higher temperatures. The influence of several parameters on the reaction was studied, in particular : the reaction temperature, the amount of shear during the mixing step (or mixing time), the number of functional units per chain in each blend component and the blend composition. For the miscible blends, a master curve for the dependence of the elastic modulus G’ as a function of reaction time could be drawn for different functionalities and blend compositions.

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Mukherjee, Achyut N., Vasilis Selimis, and Ioannis Aslanides. "Transepithelial Photorefractive Keratectomy with Crosslinking for Keratoconus." Open Ophthalmology Journal 7, no. 1 (October 18, 2013): 63–68. http://dx.doi.org/10.2174/1874364101307010063.

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Purpose: To analyse visual, refractive and topographic outcomes of combining transepithelial photorefractive keratectomy (tPRK) with simultaneous corneal crosslinking for the visual rehabilitation of contact lens intolerant keratoconus patients. Methods: Patients with topographically significant keratoconus, limited corrected vision and intolerant of contact lenses were prospectively recruited, subject to ethical approval and consent. All patients underwent single step aspheric tPRK and sequential crosslinking. Preoperative vision, refraction, corneal topography and wavefront were assessed, with postoperative assessment at 1, 3, 6, and 12 months. Results: 22 eyes of 14 patients were included in the pilot study. Mean age was 32 years (SD 6.8, range 24 to 43). Mean preoperative unaided vision was 1.39 LogMAR (SD 0.5) best corrected 0.31 LogMAR (SD 0.2). Mean preoperative spherical equivalent was -2.74 Diopters (D) (SD 4.1 range -12.25 to +7.75), and mean cylinder -2.9 D (SD 1.2, range 0 to -5.5). Mean central corneal thickness was 461um (SD 29, range 411 to 516). Vision improved postoperatively; unaided 0.32 LogMAR (SD 0.4), best corrected 0.11 (SD 0.13) (P=<0.005). Mean postoperative cylinder was -1.4D (SD1.2), significantly reduced (p<0.005). Maximum keratometry (Kmax) was stable throughout postoperative follow up. (p<0.05). Conclusions: Non topographic transepithelial PRK with simultaneous crosslinking improves vision, and may offer an alternative to keratoplasty in contact lens intolerant keratoconus. Further comparative studies to topographic PRK techniques are indicated.

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Nie, Tianming, Zhangyu Yuan, Shuang Yin, Weiran Tu, Weilin Yan, Jiajun Gao, and Xingmao Jiang. "Thermal behavior of crosslinking polystyrene resin to carbon material by one-step carbonization." Journal of Porous Materials 27, no. 1 (September 30, 2019): 249–61. http://dx.doi.org/10.1007/s10934-019-00808-9.

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Song, Guojun, Shujing Yang, Chao Yang, and Xilin She. "Foaming polypropylene prepared by a novel one-step silane-grafting and crosslinking method." Journal of Porous Materials 13, no. 3-4 (August 2006): 297–301. http://dx.doi.org/10.1007/s10934-006-8020-7.

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42

Gao, Yongsheng, Kevin Peng, and Samir Mitragotri. "Covalently Crosslinked Hydrogels via Step‐Growth Reactions: Crosslinking Chemistries, Polymers, and Clinical Impact." Advanced Materials 33, no. 25 (May 14, 2021): 2006362. http://dx.doi.org/10.1002/adma.202006362.

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Zhang, Wan, Xiaoqian Ji, Chaoxia Wang, and Yunjie Yin. "One-bath one-step low-temperature dyeing of polyester/cotton blended fabric with cationic dyes via β-cyclodextrin modification." Textile Research Journal 89, no. 9 (May 29, 2018): 1699–711. http://dx.doi.org/10.1177/0040517518779249.

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With the aim of polyester/cotton fabric one-bath one-step dyeing, polyester fabric low-temperature dyeing with cationic dyes was investigated based on β-cyclodextrin (β-CD) modification. After β-CD/citric acid (CA) modification, the hydrophilicity of the modified polyester fabric was improved obviously, which was demonstrated via moisture regain and contact angle, as well as wicking property. The optimal dyeing temperature and crosslinking agent were selected through comparing the color strength of the dyed polyester fibers. Modified polyester fabric obtained significantly enhanced color strength from 0.12 to 4 with a good leveling property when dyeing at 70℃ using CA as the crosslinking agent. β-CD modified polyester/cotton fabric displayed a K/ S value of 8.61, much higher than the value of 0.71 of the unmodified fabric with cationic dyes, showing a highly improved dyeing ability. The color fastness of β-CD modified polyester/cotton fabrics, including washing fastness, rubbing fastness, perspiration fastness and light fastness, are all over grade 3–4 when the curing temperature of 180℃ is adopted for β-CD modification, demonstrating that polyester/cotton fabric one-bath one-step dyeing can be realized based on β-CD modification.

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Chang, Y. J., Q. Zhou, W. H. Hou, Y. H. Liang, L. Ren, D. H. Sun, and L. Q. Ren. "Design and Preparation of Magnetism-Driven Intelligent Hydrogel Actuators." International Polymer Processing 36, no. 2 (May 1, 2021): 165–71. http://dx.doi.org/10.1515/ipp-2020-3904.

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Abstract Novel kinds of magnetism-driven poly N,N-dimethylacrylamide bilayer intelligent hydrogels with various nanofibrillated cellulose (NFC) contents were prepared successfully via one-step insitu free radical polymerization. The bilayer hydrogels possessed high mechanical strength, efficient swelling and steady magnetic response. With the increase of nanofibrillated cellulose content, the crosslinking density of the hydrogels increased, leading to the decrease of swelling rate and increase of mechanical strength and swelling bending degree of hydrogel actuators, respectively. Fe3O4 particles existed tightly on the micropore surfaces of the hydrogels, which built the function base of magnetic response of hydrogel actuators. The addition of Fe3O4 was irrelevant to the variation of crosslinking density. The bilayer structure exhibited high bonding strength. Based on intelligent responsive properties, bilayer hydrogels were designed as soft magnetism-driven actuators, realizing capture and transportation properties and provided material candidates for soft robots.

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Ren, Longfang, Guohui Zhao, Xuechuan Wang, Taotao Qiang, Na Wang, and Chao Han. "Hygienic Property of Microfiber Synthetic Leather Base Modified via a “Two-Step Method”." Journal of Engineered Fibers and Fabrics 9, no. 3 (September 2014): 155892501400900. http://dx.doi.org/10.1177/155892501400900305.

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A “two-step method” was adopted to improve the hygienic property of polyamide microfiber synthetic leather base. Firstly, the amino-terminal hyperbranched polyamides (NH2-HBP) synthesized by N, N'-methylene bisacrylamide (MBA) and diethylene triamine (DETA) was cross-linked to microfiber synthetic leather base pretreated with formic acid, in which glutaraldehyde was the crosslinking agent. Secondly, Gelatin hydrolysate was cross-linked to the preliminary modified microfiber synthetic leather base by using glutaraldehyde as the crosslinking agent. The modified microfiber synthetic leather base was then obtained. Hygienic performances, mechanical properties, and the micro morphology were taken as indexes to optimize the dosages of glutaraldehyde and NH2-HBP. The results show that when the glutaraldehyde dosage was 1.1 times that of the primary amino groups (the primary amino group dosage was about 0.201 mmol/g), the modification effect improved greatly. In this condition, the water vapor permeability, hygroscopicity, tensile strength, and tear strength of the base were 0.7691 g/10 cm2·24 h, 3.357 mL/g·24 h, 18.79 N/mm2, and 103.18 N/mm, respectively. These values were 86.7%, 48.8%, 19.8%, and 2.69% higher than those of unmodified base, respectively. When NH2-HBP dosage was three times that of the primary amino groups, the modification effect also improved. In this case, the water vapor permeability, hygroscopicity, tensile strength, and tear strength of the base were 0.5761 g/10 cm2·24 h, 3.274 mL/g·24 h, 18.79 N/mm2, and 103.4825 N/mm, respectively. These values were 113%, 42.3%, 3.5%, and 2.98% higher than those of the unmodified base, respectively. Meanwhile, the SEM image of the modified base showed that fiber dispersion was greatly increased in this condition.

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Smith, Raven A., Rebecca C. Walker, Shani L. Levit, and Christina Tang. "Single-Step Self-Assembly and Physical Crosslinking of PEGylated Chitosan Nanoparticles by Tannic Acid." Polymers 11, no. 5 (April 27, 2019): 749. http://dx.doi.org/10.3390/polym11050749.

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Chitosan-based nanoparticles are promising materials for potential biomedical applications. We used Flash NanoPrecipitation as a rapid, scalable, single-step method to achieve self-assembly of crosslinked chitosan nanoparticles. Self-assembly was driven by electrostatic interactions, hydrogen bonding, and hydrophobic interactions; tannic acid served to precipitate chitosan to seed nanoparticle formation and crosslink the chitosan to stabilize the resulting particles. The size of the nanoparticles can be tuned by varying formulation parameters including the total solids concentration and block copolymer to core mass ratio. We demonstrated that hydrophobic moieties can be incorporated into the nanoparticle using a lipophilic fluorescent dye as a model system.

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Wang, Zhi, Chi-Ming Chan, Shui Han Zhu, and Jiarui Shen. "Compatibilization of polystyrene and low density polyethylene blends by a two-step crosslinking process." Polymer 39, no. 26 (December 1998): 6801–6. http://dx.doi.org/10.1016/s0032-3861(98)00174-8.

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Gong, Dafei, Qinrui Lin, Zhengzhong Shao, Xin Chen, and Yuhong Yang. "Preparing 3D-printable silk fibroin hydrogels with robustness by a two-step crosslinking method." RSC Advances 10, no. 45 (2020): 27225–34. http://dx.doi.org/10.1039/d0ra04789a.

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Dzunuzovic, Jasna, Marija Pergal, Vesna Vodnik, Milena Spírková, Rafał Poręba, and Slobodan Jovanovic. "Investigation of the morphology and surface properties of crosslinked poly(urethane-ester-siloxane)s." Chemical Industry 66, no. 6 (2012): 813–21. http://dx.doi.org/10.2298/hemind121004101d.

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Two series of crosslinked poly(urethane-ester-siloxane)s were synthesized from ?,?-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4?-methylenediphenyl diisocyanate and Boltorn? hyperbranched polyesters of the second and third pseudo generation, by a two-step polymerization in solution. The effect of the EO-PDMS-EO content and functionality of the applied crosslinking agent on the morphology and surface properties of the prepared poly(urethane-ester-siloxane)s was investigated by FTIR spectroscopy, small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and water absorption measurement. Different techniques (FTIR peak deconvolution, SAXS and AFM) revealed that decrease of the crosslinking agent functionality and EO-PDMS-EO content promotes microphase separation in the synthesized poly(urethane-ester-siloxane)s. SEM analysis and water absorption experiments showed that due to the hydrophobic character of EO-PDMS-EO and its ability to migrate to the surface of poly(urethane-ester-siloxane)s, samples synthesized with higher EO-PDMS-EO content and crosslinking agent of lower functionality have more hydrophobic surface and better waterproof performances. The obtained results indicate that the synthesis of poly(urethane-ester-siloxane)s based on EO-PDMS-EO and Boltorn? hyperbranched polyesters leads to the creation of networks with interesting morphological and surface properties, which can be easily tailored by changing the content of EO-PDMS-EO segment or functionality of hyperbranched polyester.

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Mohapatra, Hemakesh, Jorge Ayarza, Emily C. Sanders, Angelique M. Scheuermann, Philip J. Griffin, and Aaron P. Esser-Kahn. "Ultrasound Promoted Step-Growth Polymerization and Polymer Crosslinking Via Copper Catalyzed Azide-Alkyne “Click” Reaction." Angewandte Chemie 130, no. 35 (July 30, 2018): 11378–82. http://dx.doi.org/10.1002/ange.201804451.

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Journal articles on the topic 'STMP crosslinking'

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