废蚕丝中丝素蛋白的琥珀酰化改性研究

文章研究采用琥珀酰酐对废蚕丝丝素蛋白进行化学改性,研究丝素蛋白浓度、琥珀酰酐用量、反应温度、反应时间对丝素蛋白琥珀酰化程度的影响。通过正交实验确定丝素蛋白琥珀酰化的适宜条件为:丝素蛋白浓度2%、琥珀酰酐用量15%、温度40℃、反应时间30 min。丝素蛋白经琥珀酰化修饰后,起泡特性与乳化特性与原来相比均有不同程度的改善。     

纳米氧化石墨烯添食育蚕制备高强度蚕丝

本文采用添食育蚕法,向五龄期家蚕喂食纳米氧化石墨烯(GO)改性的人工饲料制备改性蚕丝。利用扫描电子显微镜、红外光谱、广角X射线衍射等技术对改性前后蚕丝的结构及性能进行表征。结果表明,GO被成功导入丝素蛋白,未明显影响蚕丝表面形貌,但限制了丝素蛋白二级结构转变及结晶,明显提升了蚕丝的力学性能。     

静电纺丝射流分裂过程的探讨

以质量分数28％再生蚕丝素蛋白水溶液进行静电纺丝,结合拉曼光谱和广角X射线分析测试纤维的构象和晶体结构,探讨了纺丝过程中射流发生情况。结果表明,静电纺丝所得纤维中,仅部分丝素蛋白分子转变为β折叠构象,丝素Ⅱ晶型含量少,纤维只经历了有限的拉伸,说明静电纺丝中射流不是单一细化,而是发生了分裂。     

蚕丝蛋白在生物样本保存领域应用的研究进展

蚕丝是一种天然的高分子材料,由60%~80%的丝素、15%~35%的丝胶及约5%的石蜡、色素、糖类等杂质组成。丝素具有良好的生物相容性和降解性,在药物缓释、促进伤口愈合、组织工程支架等生物医药领域及降血糖、抑菌等医疗保健方面均具有广泛应用;丝胶包裹在丝素纤维外层,对丝素起保护作用,其不仅是非常有用的生物材料,还具有许多生物活性和药理作用,如抗氧化性、抗肿瘤活性、物理胃肠功能等作用。近年,蚕丝蛋白在生物样本保存领域的应用备受研究者关注,本文对蚕丝蛋白在生物样本低温保存和常温保存方面的应用和成果、存在的问题及未来的研究方向作一综述,以期为蚕丝蛋白在生物样本保存领域的应用提供参考。     

硫酸法水解家蚕丝及其光谱性质研究

文章用一定质量分数的硫酸溶液对家蚕丝进行水解,并利用傅里叶红外光谱仪、紫外可见分光光度计、X-射线衍射仪和扫描电镜等先进测试方法对硫酸水解家蚕丝制取丝素肽进行测试,分析家蚕丝丝素多肽的结构,为以后在食品、药品、化妆品等领域的应用提供理论数据。     

不溶性丝素薄膜制备新方法

天然丝素蛋白具有良好的生物相溶性,是一种具有广阔应用前景的生物材料,可用于酶固化、人造皮肤、人造韧带以及组织工程等各个方面。如果将丝素应用于生物材料,需要将蚕丝溶解后再制备成薄膜、管状等形状。而当丝素蛋白溶解在特定溶液中再干燥制备成各种形状后,却变得易溶于水,从而失去其在生物材料领域的应用价值。     

再生蚕丝蛋白纤维的染色性能研究

主要研究染料种类、染料质量分数、氯化钠质量浓度、染色时间、染色温度等5个因素对再生蚕丝蛋白纤维上染率的影响,分析了再生蚕丝蛋白纤维的染色性能.结果表明:对纤维素纤维染色性能较好的染料对再生蚕丝蛋白纤维也有很好的染色性能.运用直接染料对再生蚕丝蛋白纤维进行染色,得到的最佳工艺为:染料质量分数1％ (omf)、氯化钠质量浓度12 g/L、染色温度85℃、染色时间50 min.     

可溶性丝素蛋白新型脱盐工艺研究

天然丝素蛋白不溶于水,溶于强酸、强碱和一些中性盐溶液,为获得高纯度的可溶性丝素蛋白,脱盐是关键环节。将丝素蛋白经脱胶后溶解于氯化钙-乙醇-水三元体系溶液制成可溶性丝素蛋白,用扩散渗析和电渗析2种集成膜过程进行脱盐。该工艺较传统的透析袋脱盐方法,具有耗时短、脱盐率高等特点,脱盐率可达99.98%以上,回收率可达90.1%。     

再生丝素蛋白水溶液流变行为的研究

根据蚕体内丝素蛋白浓度的变化,研究了相应条件下再生丝素蛋白浓溶液的流动曲线,探讨了流变行 为中丝素蛋白分子的构象变化,并用拉曼光谱对应力作用下再生丝素蛋白分子的构象变化进一步作了讨论。     

天然丝素在化妆品中的护肤特性及应用

天然丝素是世界上最受欢迎的天然型营养化妆品添加剂之一。蚕丝经处理、加工可制成丝素粉、丝肽液、丝胶冻及丝素氨基酸等,本文详细阐述了这几种产品的加工、性能及作用机理,并提供了详细的应用配方。     

Effects of halloysite nanotubes and kaolin loading on the tensile,swelling, and oxidative degradation properties of poly(vinyl alcohol)/chitosan blends

[Halloysite nanotubes (HNT)]‐filled and kaolin filled composite films based on poly(vinyl alcohol) (PVA)/chitosan (CS) blend were prepared via solution casting method. Tensile properties, fracture morphology, FTIR spectra, thermal stability, swelling properties, moisture absorption, and oxidative degradation of the composite films were investigated. Addition of 0.5 wt% of filler led to the optimum tensile properties of the films. Increased roughness and tearing in the fracture surface morphology supported the tensile results. The FTIR results indicated there were physical interactions present in the composite films. Thermal stability of the composite films differed slightly where PVA/CS/HNT composite films showed better thermal stability than PVA/CS/kaolin composite films. Moreover, the presence of HNT and kaolin fillers in the blend reduced the swelling and moisture absorption properties of the films. Finally, the composite films were degraded by using Fenton's reagent. Degradation percentage of the composite films decreased with increasing filler loading. J. VINYL ADDIT. TECHNOL., 19:55–64, 2013. © 2013 Society of Plastics Engineers     

PVAc乳液的共聚共混改性研究

采用乳液种子聚合法合成甲基丙烯酸甲酯(MMA)、醋酸乙烯酯(VAc)的共聚乳液,再与酚醛树脂(PF)形成共混乳液。分析了甲基丙烯酸甲脂用量对乳液性能的影响,酚醛树脂对共聚乳液性能的影响。该共聚共混乳液的粘度及固含量都符合要求,稳定性好,具有良好的机械性能和耐水性。     

Study on poly(vinyl chloride) paste blending resins

Polyvinyl chloride paste blending resins were prepared by a suspension polymerization process, and the optimum ingredients and technological conditions were studied experimentally. The effect of dispersant, surfactant, and agitator design on the particle morphology was discussed. In order to improve the thermal stability of the blending resin, stabilizer was added to the polymerization system, and a special after-treatment was adopted. The effect of blending resins on the rheological and gelation characteristics of the plastisols formed and on mechanical properties, thermal stability, and foamability of the finished articles is demonstrated.     

Thermal properties of composites with bismaleimide-vinyl poly(styrylpyridine) blends

Flammability, thermal properties, and selected mechanical properties of composites fabricated with epoxy and other thermally stable resin matrices are described. Properties measured included limiting-oxygen index, smoke evolution, thermal degradation products, total-heat release, heat-release rates, mass loss, flame spread, ignition resistance, thermogravimetric analysis, and selected mechanical properties. This paper describes the properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement. The resin matrices included: XU71775/H795, a blend of vinyl poly(styrylpyridine) and bismaleimide; H795, a bismaleimide; Cycom 6162, a phenolic; and PSP 6022M, a poly(styrylpyridine). The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with those of epoxy composites. It was determined that the blend of vinyl poly(styrylpyridine) and bismaleimide (XU71775/H795) with the graphite tape was the optimum design giving the lowest heat release rate.     

热稳定剂和润滑剂对氯化聚氯乙烯树脂性能的影响

本文重点研究了钙锌复合稳定剂和有机锡稳定剂及辅助稳定剂对氯化聚氯乙烯（CPVC）树脂的动态热稳定效果,确定合理的稳定体系及配比;研究了内外润滑剂对CPVC树脂加工流动性能的影响;此外还提出CPVC管材参考配方及相应的性能指标并与国外同类产品做对比。     

双马来酰亚树脂基体的湿热特性研究

本文以四官能环氧树脂基体作参比物、选择两种典型的双马来酰亚胺树脂基体（环氧改性双马基体、烯丙基双酚Ａ／双马共聚基体）作为对象，研究其吸湿特性以及吸湿对树脂基体性能的影响，结果表明，树脂基体的化学结构和交联密度对吸湿特性有较大的影响，吸湿量对树脂基体性能的影响也与基体材料的类型，交联密度有关，不能简单地用给定时间下的吸湿率来评定树脂基体的湿热性能优劣。     

Characterization of resol resins modified by the addition of PVC plastisols

Plastisols, which are a blend of poly(vinyl chloride) resin and a plasticizer (DEHP), were used as a toughening agent of a resol resin in order to improve the mechanical properties. It was not possible to formulate resol blends by adding more than 10 % of plastisol owing to a lack of apparent homogeneity in the systems, which also showed many air bubbles. The relationship between dynamic mechanical, mechanical and thermal properties and the amount of plastisol added was studied. It was determined from the infrared spectroscopy and dynamic mechanical results that the resol–plastisol blends seem to be formed by a reaction between the phenol and PVC giving a higher crosslinked structure. An improvement in the thermal resistance of the blends at lower temperatures was observed with an increase in the percentage of plastisol. Flexural analysis showed the elastic behaviour of the systems. However, it was not possible to observe the effect of the plasticizer (DEHP) owing to the low quantity of plastisol that was added to the resol. Copyright © 2004 Society of Chemical Industry     

树脂基玻璃纤维复合材料吸湿对性能影响及其机理研究

研究了树脂基玻璃纤维增强复合材料吸湿过程及其机理。通过对玻璃纤维复合材料吸湿后相关性能的测试,了解了复合材料的吸湿行为,以及吸湿行为对相关性能的影响。研究认为树脂基体及界面的吸湿行为对材料整体性能影响很大,宏观表现为力学性能、热性能等明显下降。研究结果表明纤维复合材料吸湿性不仅取决于树脂基体,与纤维及界面均有关系。     

MECHANICAL PROPERTIES OF BISMALEIMIDE (N,N′-BISMALEIMIDO-4,4′-DIPHENYL METHANE) - VINYL ESTER OLIGOMER (VEO) MODIFIED UNSATURATED POLYESTER INTERCROSSLINKED MATRICES FOR ADVANCED COMPOSITES

An intercrosslinked network of varying percentages of N,N′-bismaleimido-4,4′-disphenyl methane (BMI), vinyl ester oligomer (VEO) modified unsaturated polyester (UP) matrices have been developed. Vinyl ester oligomer was prepared by reacting commercially available epoxy resin GY 250 (Ciba-Geigy) and acrylic acid was used as toughening agent for unsaturated polyester resin. BMI-VEO-UP matrices were characterized for their mechanical properties, viz tensile strength, flexural strength and unntoched Izod impact test as per ASTM standards. The dielectric strength and water absorption measurements were also performed according to ASTM standards. Data obtained from mechanical studies, dielectric strength and water absorption indicate that the introduction of VEO into unsaturated polyester resin improves mechanical properties and affects the moisture resistance according to its percentage concentration. The incorporation of BMI into the VEO modified unsaturated polyester system improves mechanical properties, dielectric strength and resistance to moisture absorption according to its percentage concentration.     

ACR-g-VC/纳米水滑石复合材料的形态及性能

采用原位悬浮聚合制备了丙烯酸酯共聚物(ACR)接枝氯乙烯(VC)(ACR-g-VC)树脂和ACR-g-VC/纳米水滑石复合材料,并研究了复合材料的形态、加工塑化性能、力学和热性能。采用原位聚合/熔融加工得到的ACR-g-VC/纳米水滑石复合材料中,纳米水滑石基本以初级粒子形式存在,分散性明显优于由ACR-g-VC与纳米水滑石直接熔融共混制备的复合材料。水滑石含量对原位聚合/熔融加工得到的ACR-g-VC/纳米水滑石复合材料的简支梁缺口冲击强度和储能模量影响较小,而ACR-g-VC的热稳定和加工塑化性能随纳米水滑石的引入而提高。水滑石质量分数为2%的复合材料质量损失10%的温度比聚氯乙烯提高近20℃,而塑化时间缩短至22 s。