PDAAM/PU同步互穿网络聚合物的力学性能

利用互穿聚合物网络技术(IPN),将双丙酮丙烯酰胺(DAAM)用于PU胶粘剂的改性.研究了组分比、引发剂用量、固化参数对PDAAM/PU IPN力学性能的影响.结果表明,PDAAM可以提高PU的力学性能.当DAAM的质量分数在40%时,拉伸强度及断裂伸长率都达到最大值.     

聚氨酯/环氧树脂互穿网络半硬泡沫的力学性能及吸能特性

采用同步法制备了聚氨酯/环氧树脂互穿聚合物网络(IPN)半硬泡沫。通过压缩和拉伸试验研究了泡沫材料密度对力学性能的影响。研究表明,在所研究的密度范围内,泡沫的压缩模量和屈服强度均与密度成指数关系。泡沫的拉伸模量和断裂强度与密度也存在类似的关系。利用这些方程可以很好地预测泡沫力学性能随密度的变化关系。IPN泡沫兼有较好的韧性和较高的拉伸强度。相同形变下,相同密度IPN半硬泡沫拉伸过程的单位体积吸能大于压缩过程的单位体积吸能。     

Hydrogels of collagen/chondroitin sulfate/hyaluronan interpenetrating polymer network for cartilage tissue engineering

The network structure of a three-dimensional hydrogel scaffold dominates its performance such as mechanical strength, mass transport capacity, degradation rate and subsequent cellular behavior. The hydrogels scaffolds with interpenetrating polymeric network (IPN) structure have an advantage over the individual component gels and could simulate partly the structure of native extracellular matrix of cartilage tissue. In this study, to develop perfect cartilage tissue engineering scaffolds, IPN hydrogels of collagen/chondroitin sulfate/hyaluronan were prepared via two simultaneous processes of collagen self-assembly and cross linking polymerization of chondroitin sulfate-methacrylate (CSMA) and hyaluronic acid-methacrylate. The degradation rate, swelling performance and compressive modulus of IPN hydrogels could be adjusted by varying the degree of methacrylation of CSMA. The results of proliferation and fluorescence staining of rabbit articular chondrocytes in vitro culture demonstrated that the IPN hydrogels possessed good cytocompatibility. Furthermore, the IPN hydrogels could upregulate cartilage-specific gene expression and promote the chondrocytes secreting glycosaminoglycan and collagen II. These results suggested that IPN hydrogels might serve as promising hydrogel scaffolds for cartilage tissue engineering.     

Preparation of hydrogel capsules with thermoresponsive interpenetrating polymer network using concentric two-fluid nozzles

Hydrogel capsules in which shell was composed of thermoresponsive interpenetrating polymer network (IPN) of crosslinked poly(N-isopropylacrylamide) (PNIAPM) and calcium alginate, were prepared using concentric two-fluid nozzles. To introduce different amount of PNIPAM into the capsule shell, the concentrations of the NIPAM monomer and the polymerization initiator were changed in a wide range and the characteristics of the resulting capsules were evaluated. Spherical and uniformly sized capsules were obtained under all conditions. Elemental analyses showed that the PNIPAM/alginate weight ratio increased with the increase of initial concentrations of NIPAM monomer and polymerization initiator and was proportional to the initial rate of polymerization. In addition, the thermoresponsive properties of IPN hydrogel capsule were measured at temperatures from 10 °C to 50 °C and the thermoresponsive volume change ratio was expressed as a function of the PNIPAM/alginate weight ratio raised to a power. From these results, the relationship between the experimental conditions and the amount of PNIPAM in the capsule shell was clarified, and it indicated the magnitude of volume change of IPN hydrogel capsules can be controlled by introducing the desired amount of PNIPAM in the capsules.     

蓖麻油聚氨酯/环氧互穿网络胶粘剂的粘接及热稳定性研究

采用顺序聚合法制备了蓖麻油聚氨酯/环氧互穿网络胶粘剂,利用FT-IR分析了胶粘剂结构,考察了环氧的加入量对胶粘剂的表干时间、剪切强度、热稳定性的影响。结果发现,虽然该胶粘剂虽然表干时间很长,但其剪切强度可达5.65MPa;环氧加入量在37%以内,对胶膜的特征热分解温度影响不大。     

膨体聚四氟乙烯微孔-聚氨酯复合膜的制备

由于膨体PTFE微孔膜在使用中会受到污染而影响其耐水压,通过PTFE/PU复合膜可有效解决此问题.在PTFE膜表面涂覆PU溶液可制备PTFE/PU复合膜,研究发现,PU溶液组成和固化条件对PTFE/PU复合膜剥离强度有很大影响,丁酮 DMF、乙酸乙酯 DMF、甲苯 DMF均可作为PU在PTFE膜上的涂层溶剂;先低温后高温的固化方法有利于提高复合膜剥离强度.     

Damping analysis of polyurethane/epoxy graft interpenetrating polymer network composites filled with short carbon fiber and micro hollow glass bead

A series of short carbon fiber (CF) and micro hollow glass bead (HGB) filled polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites were prepared. The damping properties, thermal stability properties as well as tensile and impact strength of IPN composites were studied systematically. Results revealed that the addition of short carbon fiber and micro HGB can significantly improve the damping properties of pure PU/EP IPN and can improve the thermal decomposition temperature. Mechanical tests showed that the tensile strength of the IPN composites could be improved after the incorporation of short carbon fiber and micro HGB, while the impact resistance of the composites was impaired after the addition of micro HGB. It is expected that the carbon fiber and micro HGB filled IPN composites may be used as structural damping materials.     

Taste masking of azithromycin by resin complex and sustained release through interpenetrating polymer network with functionalized biopolymers

Abstract

Objective: The objective was to evaluate taste masking of azithromycin (AZI) by ion exchange resins (IERs) and the formation of covalent semi interpenetrating polymer network (IPN) beads using chitosan (CS) and sodium carboxylated agarose (SCAG) for sustained release of drug.

Methods: Methacrylic acid (MAA)-based IERs were prepared by suspension polymerization method. Drug release complexes (DRCs) were prepared by different drug:resin ratios i.e. 1:1, 1:2 and 1:4. The resultant DRCs were characterized using DSC, FTIR, PXRD, in vivo and in vitro taste masking, and in vitro drug release at gastric pH. IPN beads were prepared by entrapping DRCs with bio polymers and cross linked with trisodium citrate (NaCIT), and further cross-linked with glutaraldehyde (GA) for sustained release of AZI.

Results: In vitro and in vivo taste masking studies showed that MD1:4 DRC formulation was optimal. The release of AZI from DRC was found to be very fast at gastric pH i.e. 97.37?±?1.02% within 45?min. The formation of IPN beads was confirmed by FTIR. The release of drug from IPN beads at gastric and intestinal pH was found to be “<28% and <60%”, respectively. The release kinetics showed Fickian diffusion profile for ionically cross-linked beads and zero-order release mechanism for GA cross-linking beads.

Conclusions: DRCs can be effectively used for taste masking and newly formulated IPN beads demonstrated sustained release of AZI.     

UV-radiation curing of simultaneous interpenetrating polymer network hydrogels for enhanced heavy metal ion removal

Simultaneous interpenetrating polymer network (IPN) hydrogels have been prepared by UV-initiated polymerization of a mixture of acrylamide (AM) and triethylene glycol divinyl ether (DVE-3). The consumption of each monomer upon UV-irradiation was monitored in situ by real-time infrared (RTIR) spectroscopy. The acrylamide monomer AM was shown to polymerize faster and more extensively than the vinyl ether monomer DVE-3, which was further consumed upon storage of the sample in the dark, due to the living character of the cationic polymerization. The IPN hydrogels were used to remove heavy metal ions from aqueous solution under the non-competitive condition. The effects of pH values of the feed solution and the DVE-3 content in the formulation on the adsorption capacity were investigated. The results indicated that the adsorption capacity of the IPN hydrogels increased with the pH values and DVE-3 content in the formulation. Furthermore, the synergistic complexation of metal ions with two polymer networks in the IPN was found in the adsorption studies. Adsorption kinetics and regeneration studies suggested that the IPN hydrogels could be used as fast-responsive and renewable sorbent materials in heavy metal removing processes.     

Synthesis and characterization of polyurethane/polybutyl methacrylate interpenetrating polymer networks

A series of castor oil based polyurethane (PU) and poly (butyl methacrylate) (PBMA) interpenetrating polymer networks (IPNs) (PU/PBMA; 80/20, 60/40, 50/50, 40/60 and 20/80) were prepared by sequential polymerization method using toluene diisocyanate (TDI), dibutyl tin dilaurate (DBTL) as catalyst and ethylene glycol dimethacrylate (EGDM) as crosslinker. Tensile strength, percentage elongation at break and surface hardness; FTIR and optical properties of the IPNs are reported. Thermo gravimetric analyzer (TGA) studies of the IPNs are performed in order to establish their thermal stability. TGA thermogram shows that the thermal degradation of IPN was found to proceed in three steps. The microcrystalline parameters such as crystal size (N) and lattice disorder (g in%) of IPNs have been estimated using wide angle X-ray scattering (WAXS) studies. The surface morphology of the IPNs has been studied using scanning electron microscope (SEM).     

丙烯酸/淀粉/SPS互穿网络高吸水树脂的合成研究

采用浓硫酸磺化法制备了聚乙烯醇硫酸钠(SPS),以丙烯酸、淀粉和SPS为原料采用水溶液聚合法合成了淀粉接枝丙烯酸-聚乙烯醇硫酸钠互穿网络高吸水性树脂(SA-IP-SPS).红外光谱、扫描电镜分析结果表明了产品互穿网络结构的形成.合成反应的最佳条件为:w(淀粉)=6.7%;反应温度:70℃;中和度(DN):90%;w(交联剂)=0.067%;w(引发剂)=0.27%;w(SPS)=8%.在优化的聚合条件下,产品的吸蒸馏水倍率和吸盐水倍率分别可达到962g/g和112g/g.     

In vitro calcification of UHMWPE/PU composite membrane

Polyurethane composite made from biaxially drawn ultrahigh molecular weight polyethylene (BDUHMWPE) is likely an alternative for polyurethane currently being plagued for medical applications. In this study, an in vitro calcification protocol was used to determine the relative resistance to calcification of the composite membranes. The results demonstrated that the composite membranes were susceptible to extrinsic calcification that was closely related to the matrix polyurethane material used. The calcification of the composite was different from that of the solution cast polyurethane membranes. The incorporation of hydrophobic reinforcement BDUHMWPE effectively postponed the calcification. The differences of calcification between composite and polyurethane were greatly due to the differences in surface structures and properties of the as-cast polyurethane.     

PU/PVC复合膜的制备及应用

采用湿法相转化法制备了PU/PVC/SiO2复合膜,并用膜性能测试仪、扫描电子显微镜测试了膜的性能与结构.结果显示:SiO2的加入,可改善PU杂化膜的微孔结构并优化膜的性能,在该体系中加入PVC和PU共混,可以提高成膜速度及微孔结构,水通量和截留率得到了明显的提高.将制得的超滤膜用于处理麻杆蒸煮废液取得了较好的效果,与PU复合膜的对卵清蛋白的截留测试结果是一致的.     

分离润滑油中脱蜡溶剂的有机硅膜的制备

以聚二甲基硅烷为分离膜材料,正庚烷为溶剂,正硅酸乙酯为交联剂,二桂酸二丁基锡为催化剂,聚四氟乙烯膜为基膜,制得聚二甲基硅氧烷/聚四氟乙烯复合膜,用于脱蜡润滑油与溶剂(甲苯和丁酮)的分离.研究了溶液配方、硫化温度、硫化时间等因素对膜性能的影响.在操作压力2.0MPa,溶液温度20℃,进料溶剂质量分数85%条件下,膜对油的截留率为84%,通量为4.8kg/(m2·h).     

Preparation,damping and thermal properties of potassium titanate whiskers filled castor oil-based polyurethane/epoxy interpenetrating polymer network composites

A series of potassium titanate whiskers (PTW) filled castor oil-based polyurethane (PU)/epoxy resin (EP) interpenetrating polymer network (IPN) composites were prepared. The damping properties, thermal stability as well as tensile strength of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of PTW can significantly improve the damping properties of pure PU/EP IPN and can improve the thermal decomposition temperature. Tensile tests showed that the tensile strength of the IPN composites was improved after the incorporation of PTW. It is expected that the PTW filled IPN composites may be used as structural damping materials.     

Morphologies and properties of polyurethane/epoxy resin interpenetrating network nanocomposites modified with organoclay

Polyurethane/epoxy resin interpenetrating network nanocomposites containing various contents of organophilic montmorillonite (oM-PU/EP nanocomposites) were prepared by a sequential polymeric technique and an in situ intercalation method. Transmission electronic microscopy and scanning electronic microscopy analysis showed that the interpenetrating process of PU and EP increases the exfoliation degree of organophilic montmorillonite (oMMT), and that oMMT improves the compatibility and phase structure of polyurethane/epoxy resin interpenetrating polymer networks (PU/EP IPNs). Tensile test, differential scanning calorimetry and thermal gravity analysis proved that the mechanical and thermal properties of the oM-PU/EP nanocomposites are superior to those of the pure PU and PU/EP IPNs.     

An aligned fibrous and thermosensitive hyaluronic acid-puramatrix interpenetrating polymer network hydrogel with mechanical properties adjusted for neural tissue

Journal of Materials Science - Central nervous system (CNS) injuries such as stroke or trauma can lead to long-lasting disability, and there is no currently accepted treatment to regenerate...     

Damping performance of polymer blend/organic filler hybrid materials with selective compatibility

An organic hybrid system consisting of poly(ethyl acrylate) (AR), chlorinated polythylene (CPE), and N,N-dicyclohxyl-2-benzothiazolysulfenamide (DBS) was prepared as a new type of damping material. From the DSC measurements, DBS was supposed to be compatible with CPE and incompatible with AR in an organic hybrid system. Temperature dependence of loss tangent (tanδ) for the above AR/CPE/DBS hybrids showed double peaks at a temperatures of glass transition region (T_g). When a component of a weight fraction (wt.%) of AR/CPE/DBS was 37.5:12.5:50, the T_g difference (ΔT) was increased. The damping property of this system characterized by a tanδ peak area (TA) was 62.0, which is more improved than those of single component: 54.8 for only AR, 38.9 for only CPE, respectively. The three-component organic hybrids showed a selective compatibility with CPE and DBS, where we observed a high damping performance in a wide temperature range.