Biodegradable porous organosilicone‐modified collagen fiber matrix: Synthesis and high oil absorbency

We used hexadecyl trimethyl ammonium bromide as a phase transfer catalyst (PTC) to enhance the effectiveness of a heterogeneous reaction system composed of collagen fiber (CF) and organosilicone modifying agents including epoxy‐polydimethylsiloxane (ES) and/or γ‐glycidoxypropylthrimethoxysilane (GS), in order to improve oil sorption behaviors of the modified products as sorbents. The effects of PTC dosage, organosilicone species or its dosage on the degree of modification of CFs were studied, and the optimum conditions were determined. Subsequently, the surface chemistry and porous structure of the prepared sorbents were thoroughly characterized, and their oil sorption behaviors were also investigated. It was confirmed that both their hydrophobicity‐oleophilicity character and pore structures could be significantly improved by introducing PTC agent and modulating the species or amount of organosilicone, resulting in improved oil sorption behaviors. In addition, the organosilicone modified CF matrix possessed acceptable reusability and biodegradability, and can be implemented as an eco‐friendly sorbent for oil spill cleanup. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46264.     

新型胶原基人工皮肤模型的建立

根据皮肤的组织结构与生理功能,研制了复合天然三维网络结构胶原组织工程支架材料,并以此为支架材料建立了3层结构的人工皮肤模型:上层是具有良好生物相容性且可降解的聚合物涂层,可以屏蔽细菌并保持人工皮肤良好的透水气性;中间是复合型天然三维网络结构胶原纤维支架材料层,为细胞的增殖提供三维空间和良好的生长环境,起到真皮基质的作用;下层是药物层,具有营养、抗菌消炎、刺激细胞生长的作用。     

Analysis of variations in porosity of metal crosslinked collagen matrix

The fundamental knowledge of the porous nature of crosslinked collagen matrix such as tanned leather is an aid to design appropriate chemicals for leather making. It would also help to target a particular area of matrix to improve its uniformity and other functional properties. The purpose of this study is to analyze the variations in pore sizes of chromium crosslinked collagen matrix, chrome tanned leather, from different animal species and different areas of the same species. In this study, chrome tanned leather from goat and sheep were investigated for surface area, pore size, and distribution. Thermoporometry results show that average pore radius of goat leather is around 2–30 nm and that of sheep is 2–20 nm. Nitrogen adsorption result shows that average surface area of goat (8.24 m²/g) leather is higher than sheep (6.73 m²/g), but the average pore diameter of goat (289 nm) is smaller than sheep (385 nm) leather. It has been found that more numbers of smaller pores are present in goat than sheep leather and all the leather samples including goat and sheep obeyed type‐III adsorption isotherm. Capillary flow porometry analysis gives the smallest, largest, and mean‐flow‐diameter of through‐pores. The average size of largest throat pore diameter of sheep (1313 nm) is smaller than that of goat (1385 nm) leather. In general, the pore volume distribution of sheep leather is higher than that of goat leather. Morphological analysis using scanning electron microscopy shows that pore mouth of goat is deeper than that of sheep. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40835.     

Oil sorption behaviors of porous polydimethylsiloxane modified collagen fiber matrix

A facial and cost‐effective synthesis method of converting the leather protein solid wastes into a value‐added collagen matrix oil sorbent is successfully established for the first time. Hide powder fiber (HPF) was firstly prepared by using the pre‐tanned fleshing wastes from the leather industry, and then cross‐linked with epoxy‐terminated polydimethylsiloxane (PDMS) to produce hydrophobic collagen fiber, which was verified by the FT‐IR spectrum and contact angle analysis. Subsequently, a series of porous PDMS modified collagen‐based sorbents with roughness surface was successfully fabricated by solvent‐ and freeze‐drying methods respectively. The oil sorption capacity, sorption saturated time and retention capacity of the prepared sorbents was investigated. Combined with the SEM images, liquid displacement method and contact angle analysis, the results revealed that oil sorption capacities of the sorbent with lower pore size, higher porosity and rougher surface for silicone oil, motor oil and vegetable oil were approximate to 13.60, 12.50, and 11.92 g/g, respectively. Additionally, the sorption of oils is a quasi‐instantaneous process and also showed excellent oil retention capacity. It exhibited acceptable oil sorption performances as compared to commercial biomass sorbents. These findings indicated its potential as an eco‐friendly oil sorbent material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42727.     

Properties of composite films comprising surface modified fine collagen particles dispersed in polyurethane matrix

Collagen-rich natural leather powders (PPd) with average particle size of 12 μm were modified and dispersed in a polyurethane (PU) matrix. Three kinds of surface modification techniques were employed; surface polyaddition of PU, copolymerization with acrylamide (AAm), and grinding of the PPd with PU powder in a planetary ball mill. Surface modification was confirmed mainly by FTIR signals from the modifier. The DTA exothermic peak shifted toward a higher temperature by 260 K when copolymerized with AAm. On the copolymerized sample, the IR peak due to C(DOUBLE BOND)O stretching appeared between those of the original AAm and PPd, indicating the mutual chemical interaction. The tensile yield stress and critical strain of the composite films increased by surface modification with PU, while the latter decreased for the film containing the PPd powders copolymerized with AAm. Judging from the micrographs of the expanded films, the increase in the adhesive strength between the powder surface and the matrix after modification by AAm was larger than those by PU. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1693–1700, 1997     

Porous organosilicone modified gelatin hybrids with controllable and homogeneous in vitro degradation behaviors for potential application as skin regeneration scaffold

This work aims at investigating intensively the effects of organosilicone species and their dosage on the physicochemical and particularly the in vitro degradation properties of gelatin hybrids. We prepared various porous organosilicone modified gelatin hybrids with epoxy‐polydimethylsiloxane (PDMS) and/or glycidoxypropyltrimethoxysilane (GPTMS) and further systematically investigated their degradation behaviors in simulated physiological environments. It was found that the chemical composition, thermal stability, crosslinking degree, mechanical properties and porous structure of the gelatin hybrids could be tuned by adjusting the amount of PDMS and GPTMS. More importantly, degradation rates of the gelatin hybrids were reduced with increasing content of GPTMS, implying that the degradation behaviors could be controlled by tailoring the chemical interaction between the gelatin and organosilicone moieties. In addition, gelatin hybrids modified with both PDMS and GPTMS (PGs‐GE) were demonstrated as a homogeneous hybridization, and their maximum weight losses met the typical healing period of a normal skin wound. Noticeably, the P1G1‐GE hybrid with PDMS to GPTMS molar ratio 1:1 exhibited appropriate weight loss, integrity of pore structure and synchronous dissolution of silicon and protein during the degradation process, indicating a homogeneous degradation behavior. Furthermore, both the original and degraded P1G1‐GE hybrid exhibited favorable cytocompatibility in vitro. The findings will be helpful for further insight into the in vivo degradation of gelatin hybrids, suggesting their potential application as skin regeneration scaffolds. © 2019 Society of Chemical Industry     

Polymer networks based in (4‐vinylbenzyl)‐N‐methyl‐D‐glucamine supported on microporous polypropylene layers with retention boron capacity

New cellulose porous layers, with capacity to transport and retain boron from aqueous solution, were developed via interpenetrating polymer network (IPNs). These polymer systems were made to assemble mimetic systems of plant root tissue for the study of available boron transport. For that cellulose porous layers supported on polypropylene matrix were used as primary network for the formation of IPN. A vinyl monomer, (4‐vinylbenzyl)‐N‐methyl‐d ‐glucamine (VbNMDG), was synthesized at three concentration levels and cellulose ultrafiltration membranes were modified by in situ polymerization in the inside of the pores. Change of hydrophilicity, percent of secondary network, permeability and retention properties were studied. The formation of IPNs in the inside of the pores decreased the permeabilities of polymer layers. In addition, a decrease of hydrophilicity was seen. A linear increase of boron retention in function of VbNMDG concentrations was observed for the different boron concentrations and a negative effect on retention capability was evidenced for several charge and discharge cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40653.     

Self‐assembled polymer nanocomposites and their networks

Synthetic modifications to block‐copolymer structure‐directing agents lead to polymerizable macromers suitable for templating the growth of mesoporous silica particles, which can subsequently react in situ to form extended nanocomposites and nanocomposite networks. Suitably functionalized triblock polymers can preserve the structure‐directing capabilities of the triblock polymer for templating ordered mesoporous silica particle growth and also generate a reactive matrix for subsequent polymer network formation via the reactive end groups. The final self‐assembled products are polymer nanocomposites or novel crosslinked nanocomposite networks whose organic/inorganic composition ratios can vary systematically. The novel self‐assembly route described here should be generally applicable to the synthesis of intimately mixed nanocomposites and nanocomposite networks, starting from a wide variety of block polymeric template/macromer/ordered silica systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41111.     

GMA‐based emulsion‐templated solid foams: Influence of co‐crosslinker on morphology and mechanical properties

Highly open porous polymer foams formed from high internal phase emulsions (polyHIPEs) are attracting significant interest because of their potential applications in many areas of advanced materials science. In this work, the influence of the crosslinker or co‐crosslinkers of different molecular weights on the morphology and mechanical properties of polyHIPEs containing glycidyl methacrylate (GMA) was studied. Several poly(ethylene glycol) dimethacrylate (PEGDMA) crosslinkers were considered. The results show that introducing higher molecular weight crosslinkers into polyHIPEs produces a more open structure, with significantly increased compression strength and deformation at breakage. This eliminated the undesirable brittleness and chalkiness commonly found in polyHIPE materials. The Young's modulus of GMA‐based polyHIPEs containing 40% poly(ethylene glycol) dimethacrylate increased by 50% and the crush strength by 400% when compared with traditional GMA/ethylene glycol dimethylacrylate polyHIPEs. This improvement in mechanical properties is expected to improve the suitability of polyHIPEs for use in a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46295.     

Effects of shell crosslinking on polyurea microcapsules containing a free‐radical initiator

Microencapsulation of a material is often used when a controlled release of a substance is desired. This study examines the effects of crosslinking in polyurea microcapsule shells on stability of microcapsules containing the free‐radical initiator cumene hydroperoxide (CHP). Crosslinking of polyurea shells was varied by using amine monomers containing different amine functionalities, and/or changing the isocyanate/primary amine ratio. Thermogravimetric analysis was performed to determine thermal properties of these microcapsules, and the pot lives of monomer systems containing these microcapsules were measured. Thermal stability is greater with a moderate degree of crosslinking from a trifunctional amine, and decreases when crosslinking is increased through use of higher amine functionality. Stability in monomer media generally increases with increased crosslinking through higher amine functionality, but is less predictable due to crosslinks formed between capsules. Generally, increasing crosslinking through altering the isocyanate to primary amine ratio decreases capsule stability in both dry and monomer storage. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42408.     

Chitosan/gelatin porous bone scaffolds made by crosslinking treatment and freeze‐drying technology: Effects of crosslinking durations on the porous structure,compressive strength,and in vitro cytotoxicity

In this study, freezing was used to separate a solute (polymer) and solvent (deionized water). The polymer in the ice crystals was then crosslinked with solvents, and this diminished the linear pores to form a porous structure. Gelatin and chitosan were blended and frozen, after which crosslinking agents were added, and the whole was frozen again and then freeze‐dried to form chitosan/gelatin porous bone scaffolds. Stereomicroscopy, scanning electron microscopy, compressive strength testing, porosity testing, in vitro biocompatibility, and cytotoxicity were used to evaluate the properties of the bone scaffolds. The test results show that both crosslinking agents, glutaraldehyde (GA) and 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide, were able to form a porous structure. In addition, the compressive strength increased as a result of the increased crosslinking time. However, the porosity and cell viability were not correlated with the crosslinking times. The optimal porous and interconnected pore structure occurred when the bone scaffolds were crosslinked with GA for 20 min. It was proven that crosslinking the frozen polymers successfully resulted in a division of the linear pores, and this resulted in interconnected multiple pores and a compressively strong structure. The 48‐h cytotoxicity did not affect the cell viability. This study successfully produced chitosan/gelatin porous materials for biomaterials application. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41851.     

不同来源胶原肽对光老化皮肤成纤维细胞的影响研究

比较研究了海蜇、牛骨和鳕鱼皮3种不同来源胶原肽对光老化皮肤成纤维细胞的修复作用。发现3种胶原肽均可显著提高光老化细胞的细胞增殖活性,经紫外照射后,人皮肤成纤维细胞Ⅰ型、Ⅲ型胶原蛋白及透明质酸合成量明显降低,表现为差异性极显著(P0.01),同时细胞内抗氧化酶系T-SOD、CAT和GSH-Px的抗氧化酶活力也都降低。当加入3种胶原肽后,光老化细胞的Ⅰ型、Ⅲ型胶原蛋白及透明质酸合成量与细胞内T-SOD、CAT和GSH-Px酶活力均有所增加,且改善光老化细胞内抗氧化酶活力与增加细胞胶原分泌效果较好的是海蜇胶原肽。     

驴皮中胶原蛋白的提取及其特性研究

分别采用酸法和酶法提取驴皮胶原蛋白,并测定了所提取胶原蛋白的性质。结果表明,两种方法提取的胶原蛋白紫外最大吸收峰都在234 nm处,在280 nm处吸收较小;两者红外吸收光谱相似,并且都具有三股螺旋结构;电泳图谱分析所得胶原蛋白的亚基组成形式为(α1)2α2,推测所提取的是Ⅰ型胶原蛋白;DSC(示差量热扫描法)测定发现,酶溶性胶原蛋白的热收缩温度(65.33℃)高于酸溶性胶原蛋白(50.90℃);羟脯氨酸测定发现,酶法提取驴皮胶原蛋白的纯度高于酸法提取驴皮胶原蛋白的纯度。     

Hypercrosslinked silole‐containing microporous organic polymers with N‐functionalized pore surfaces for gas storage and separation

Novel hypercrosslinked microporous organic polymers (MOPs) derived from N‐functionalized siloles as basic building units have been designed and synthesized via Friedel–Crafts alkylation reaction. The resulting N‐functional silole‐containing polymer networks exhibit high thermal stabilities and moderate Brunauer–Emmett–Teller surface area ranging from 666 to 1137 m² g^?1. The incorporation of carbazole or triphenylamine moieties into the polymer skeleton increases the number of electron donating basic nitrogen sites in the porous frameworks. Thus, the corresponding polymer PDMCzS shows enhanced CO₂ adsorption capacities of 3.23 mmol g^?1 at 273 K and 1.13 bar, and higher CO₂/N₂ selectivity (43.99) at 273 K than the analogous silole‐containing polymers P1–P3. These results demonstrated that the N‐functionalized silole‐containing polymer network is a very promising candidate for potential applications in post‐combustion CO₂ capture and sequestration. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45907.     

Correlations between pore structure parameters and gas permeability of corundum porous materials

Corundum porous materials with different contents of calcium hexaluminate formed in situ were prepared using pure calcium aluminate cement as the calcium source. The surface fractal dimensions of the porous materials were calculated based on the experimental data of mercury intrusion. Correlations between pore structural parameters and the permeability coefficients k₁ and k₂ of the porous materials were then studied based on the grey system theory. The results showed that pores in the corundum porous materials have great fractal characteristics. The surface fractal dimension was a significant pore structural parameter that reflected the complexity of pore shape, pore surface, and pore-size distribution, which had the maximum correlation coefficient with the permeability of this type of porous materials. The apparent porosity and pore-size distribution had relatively high correlation coefficients to the permeability as well. Increasing the apparent porosity and the volume percentage of larger pores, and decreasing the volume percentage of smaller pores all benefited the permeability of the porous materials. In addition, the mean pore size and median pore size showed lower correlation coefficients to the permeability—especially for porous materials with a wide pore-size distribution.     

Preparation and characterization of bismaleimide (N,N′‐bismaleimido‐4,4′‐diphenyl methane)–unsaturated polyester modified epoxy intercrosslinked matrices

An intercrosslinked network of unsaturated polyester–bismaleimide modified epoxy matrix systems was developed. Epoxy systems modified with 10, 20, and 30% (by weight) of unsaturated polyester were made by using epoxy resin and unsaturated polyester with benzoyl peroxide and diaminodiphenylmethane as curing agents. The reaction between unsaturated polyester and epoxy resin was confirmed by IR spectral studies. The unsaturated polyester toughened epoxy systems were further modified with 5, 10, and 15% (by weightt) of bismaleimide (BMI). The matrices, in the form of castings, were characterized for their mechanical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the matrix samples were performed to determine the glass transition temperature (T_g) and thermal degradation temperature of the systems, respectively. Mechanical properties, viz: tensile strength, flexural strength, and plain strain fracture toughness of intercrosslinked epoxy systems, were studied by ASTM methods. Data obtained from mechanical and thermal studies indicated that the introduction of unsaturated polyester into epoxy resin improves toughness but with a reduction in glass transition, whereas the incorporation of bismaleimide into epoxy resin improved both mechanical strength and thermal behavior of epoxy resin. The introduction of bismaleimide into unsaturated polyester‐modified epoxy resin altered thermomechanical properties according to their percentage concentration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2853–2861, 2002     

Comprehensive insight of crosslinking agent concentration influence on starch-based aerogels porous structure

In this work, we evaluated starch-based aerogels prepared using freeze-drying, and an eco-friendly crosslinking agent (trisodium citrate), in three different concentrations: 12.8, 19.3, and 25.7 mg ml⁻¹. Aerogels were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, relative density, porosity percentage, scanning electron microscopy (SEM), and water uptake. The results indicated a higher reticulation and crystallinity and lower water uptake, increasing crosslinking agent concentration (Aero 1:2). SEM images revealed the prominent presence of macroporous structure (more than 50 nm) within the aerogel, containing small and large pores within the aerogel structure. The small pores were statistically similar for Aero 1:1 and Aero 1:1.5, as observed by analysis of variance analysis, but they were statistically different from Aero 1:2. The large pores diameter increased with higher crosslinking concentration and induced them as closed pores, resulting in a less porous structure. This result is directly associated with a higher reticulation degree. Overall, the influence of crosslinking agent concentration was studied and indicated that Aero 1:1.5 presented valuable properties.     

Modulating stability and mechanical properties of silica–gelatin hybrid by incorporating epoxy‐terminated polydimethylsiloxane oligomer

Silica‐gelatin hybrids, particularly GT‐G hybrids prepared by crosslinking gelatin (G) with γ‐glycidoxypropyltrimethoxysilane (GT), have attracted much attention in tissue engineering for diverse applications in hard or soft tissue regeneration; however, scaffolds with tunable properties are needed to meet specific requirements. In this work, a silica‐gelatin hybrid (ES/GT‐G) was synthesized by incorporating epoxy‐terminated polydimethylsiloxane oligomer (ES) to modulate the properties of GT‐G hybrid. The ES/GT‐G hybrid sponge presented a 3D network structure with porosity 86.4% ± 0.9%, determined by the liquid displacement method, and average pore size 340 ± 36 μm, determined by SEM observation. Compared with GT‐G hybrid material, the prepared ES/GT‐G hybrid wet film showed a decrease of tensile strength from 2.79 ± 0.04 MPa to 1.87 ± 0.12 MPa, with an increase of elongation at break from 19.96 ± 0.66% to 29.86 ± 0.87%, and the ES/GT‐G hybrid sponge exhibited a decline of compressive yield strength from 1.21 ± 0.04 MPa to 0.72 ± 0.06 MPa, based on the tensile and compression tests respectively. The introduction of ES enhanced the thermal denaturing temperature of GT‐G by 5°C as determined by a DSC study, and increased in vitro biodegradation slightly, without significantly changing surface wettability and swelling behavior. These findings suggest that silica‐gelatin hybrids with tunable properties are promising for applications from hard to soft tissue regeneration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43059.     

Some factors affecting pore size in the synthesis of rigid polymer monoliths: Theory and its applicability

Macroporous monoliths represent now widely used materials whose successful application strongly depends on their characteristics. Among those the average pore size is one of the key parameters. In this paper, we consider the applicability of theoretical calculations for the selection of appropriate porogens to generate the materials with required average pore size. A set of macroporous poly(meth)acrylate monoliths was synthesized via thermo- and photo-initiated free radical polymerization and characterized in regards to their average pore size. Additionally, the difference in solubility parameters as well as Hansen's solubility parameter distance between monomers and porogens were calculated for each polymerization mixture using Hildebrand's and Hansen's solubility theories. The theoretical predications and experimental data were compared and analyzed to establish the applicability of theoretical calculations to previse average pore size for different systems. It was found that Hildebrand's theory seems to be poorly appropriate as universal tool, while Hansen's theoretical approach explained better the efficiency of solvents as porogens. The application of oligomers and polymer solutions due to the increase of viscosity as well as the variation of crosslinker amount in the monomer system can be singled out as Hansen's theory limitations at the prediction of the average pore size.     

Influence of annealing treatment on the structure and properties of poly(4‐methyl‐1‐pentene)‐based films and membranes

The poly(4‐methyl‐1‐pentene) casting films were prepared by melt extrusion and annealed below the melting temperature. The effect of annealing conditions on the structure and properties of casting films and stretched membranes was discussed. In this work, a new peak around annealing temperature, as shown in melting curves, revealed the increase in thickness of lamellar structure. Annealing treatment led to improvements of amorphous thickness and crystal orientation. And the thickness of crystal phase correlated with the logarithm of annealing time. The increase in annealing temperature or time led to the improvements of the hard elasticity of samples. Additionally, the larger porosity of stretched membranes was observed as the annealing time and temperature increased. An optimum annealing condition to prepare microporous membranes was 30 min, 200 °C. This work also discussed the importance of annealing treatment in the preparation of microporous membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46491.