用纳米SiO2改性胶乳制备新型医用橡胶手套

用纳米SiO2改性胶乳制备新型医用橡胶手套;纳米SiO2; 天然胶乳; 医用手套; 性能     

医用乳胶手套中水溶性蛋白质的含量分析

本文采用改进的Lowry法对医用乳胶手套中水溶性蛋白质析出量进行了测定,并探讨了乳胶手套中水溶性蛋白质析出量与提取时间的关系.统计学结果显示:2 h、4 h和8 h组所测得的蛋白质析出量均值分别为124.14±29.09 μg/g、 183.58 ±33.22 μg/g和190.58±29.97 μg/g.通过t检验,2 h组和4 h组相比较,2 h组和8 h组相比较,差异均有高度统计学意义(p=0.000);4 h组和8 h组相比较,差异无统计学意义(p=0.563).     

亲水性聚硅氧烷改性天然乳胶的性能

以亲水性聚硅氧烷KGF-903共混改性天然乳胶,通过拉力试验、老化试验、接触角测量和扫描电子显微镜等研究了聚硅氧烷的添加量对天然乳胶力学性能、抗老化性能、亲水性能和表面形貌的影响。结果表明,KGF-903含量在1.5%时拉伸强度有最佳的改性效果;KGF-903添加量约为3%时断裂伸长率达到最大,老化前后的断裂伸长率比改性前分别提高57%和50%。随着KGF-903含量的增加,改性天然乳胶片的水接触角逐渐减小;扫描电子显微镜观察的结果表明,添加聚硅氧烷能改变乳胶的分散状态。利用小试的最佳配方(即KGF-903的添加量为1.5%)生产了2批次医用导尿管,其表面光洁度、导尿管球囊的成品率、管身硬度、连接器与导尿管排泄锥形接口所承受的拉力和充气漏斗与引流漏斗连接处所承受的拉力等均有显著的提高,有效改善了产品的质量。     

胶乳法溴化天然橡胶的结构与性能

在胶乳状态下制得不同溴含量的溴化天然橡胶产物,并采用傅里叶红外光谱和1H NMR核磁共振测试技术对胶乳法溴化天然橡胶（BNR）的结构进行了表征,用扫描电子显微镜对BNR的形貌进行了观察,考察了不同溴含量BNR的溶解性能和氮含量。红外光谱分析表明,天然胶乳溴化反应时发生了溴化取代和加成反应;1H NMR分析结果则证实存在C=C双键加成和亚甲基、甲基的溴化取代。 随着溴含量的增加,BNR产物逐渐变得硬而脆,最终呈粉末状,且粒径减小。 同一溴化天然橡胶产物在不同溶剂中的溶解能力由小到大依次为：四氯化碳、苯＜甲苯、二甲苯＜四氢呋喃＜三氯甲烷＜环己酮;在同一有机溶剂中BNR的溶解性能则随着溴含量的增加而增大。 BNR产物的含氮量随着溴含量的增加而减小,当溴含量为42％时,氮含量减小至0.10％。     

Blending of Natural Rubber/Recycled Ethylene-Propylene-diene Rubber: Promoting the Interfacial Adhesion Between Phases by Natural Rubber Latex

This article deals with blends based on natural rubber (NR) and recycled ethylene-propylene-diene rubber (R-EPDM). Natural rubber latex (NRL) was introduced into the blends to enhance interfacial adhesion between NR and R-EPDM. A new route of compounding was also suggested. The blends were prepared by mixing R-EPDM and other additives in NRL before blending with natural rubber on a two-roll mill. By applying this method, the homogeneity of the blends and cross-linking distribution are significantly improved. The blends exhibited superior state of cure, swelling resistance, mechanical properties and dynamic mechanical properties. The degree of entanglement between NR and R-EPDM also increased after NRL modification.     

Radiation Graft Copolymerization of n-Butyl Acrylate on Natural Rubber Latex

Abstract

A method of radiation graft copolymerization of n-butyl acrylate (NBA) on natural rubber (NR) latex has been studied. The rate of conversion increases with the increase of NBA in latex. An irradiation dose of about 12 kGy is needed to obtain 90% conversion with 40 phr of NBA in latex. Tensile strength, tear strength, and elongation at break of grafted NR are found to decrease with increasing degree of grafting. The physical strength of a vulcanizate prepared from a mixture of NR and ply-NBA was found to be better than that of NBA-NR graft copolymer vulcanizate. The graft copolymerization reaction takes place in the outer layer of NR particles, and because the secondary bonds between poly-NBA molecules may be weaker than those between NR molecules, the existence of a poly-NBA layer in NR particles will decrease its physical strength.     

丝胶接枝水性聚氨酯乳液对天然乳胶的改性研究

利用丝胶优良的生物相容性、抗氧化性等特点,结合水性聚氨酯优良的机械性能,合成了丝胶接枝水性聚氨酯乳液(1)。采用杂凝聚技术用1改善天然乳胶手套的机械性能和过敏性。结果表明,经1改性后的天然乳胶手套在断裂伸长率基本不变的情况下,断裂强度有了明显的提高;杂凝聚方法形成的核壳结构使丝胶包裹在手套的内表面,达到了改善过敏性的目的。     

核壳结构三元含氟丙烯酸酯乳液的制备及表征

以甲基丙烯酸三氟乙酯(Actyflon-G03)、丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)为原料,采用质量比为 1/1 的 OP-10/SDS 复合乳化荆,利用种子乳液聚合法,合成了核壳结构共聚物乳液.研究了温度对聚合反应、氟单体含量对聚合物膜吸水性及硬度的影响,采用 DSC、SEM-EDX、TEM 表征了共聚物膜的性能及乳胶粒子特征.结果表明:当 Actyflon-G03 含量为 23.28%时,核壳型结构粒子呈球形分布,粒径约为 80～110 nm,膜吸水率最低,硬度最高,并有 75.85%的最大转化率和 0.58%的最低凝胶率.SEM-EDX 分析显示,氟原子在成膜过程中向膜表面迁移,降低了膜的表面能.     

天然胶乳中蛋白质和磷脂对橡胶分子结构的影响

采用碱性蛋白酶和磷脂酶处理天然胶乳,制备脱蛋白胶乳和脱脂胶乳,结合原子吸收光谱仪、核磁共振交联密度仪、凝胶色谱(GPC)等仪器对处理前后的天然胶乳进行了分析。通过对比分析,发现酶处理后胶乳分子量降低,分子量分布变宽,金属离子浓度、凝胶含量和交联密度均降低。结果表明,金属离子与天然橡胶中的蛋白质、磷脂间存在着物理的或化学的作用力;蛋白质、磷脂在天然橡胶中起到节点的作用,有利于形成分子间交联,增大天然橡胶分子量,形成分子间网络结构。     

Preparation and Study of Epoxidized Natural Rubber

Epoxidized natural rubbers (ENRs) with different extents of epoxidation (B) were prepared under various reaction conditions. The effects of the amount of H₂O₂ and the reaction time on B are discussed. The glass transition temperature T_g, the thermal degradation temperature and the activation energy of thermal degradation of the ENRs increase with B. The results indicate that the thermal stability of the ENRs increases with B.This revised version was published online in November 2005 with corrections to the Cover Date.     

遥爪型液体天然橡胶的合成与表征

以天然橡胶(NR)为原料,经环氧化反应在NR分子链上引入环氧基制得环氧化天然橡胶(1);1经裂解反应合成了端羰基液体天然橡胶(2);对2进行改性得到端羟基液体天然橡胶(3),其结构经1H NMR和IR表征。探讨了反应温度、时间、氧化剂用量和环氧化程度对2的黏均分子量(M珚η)的影响。结果表明,延长反应时间、升高温度和增加氧化剂用量均可有效降低2的M珚η;1的环氧化程度对2的M珚η具有决定性作用,可通过调节环氧化程度实现2的M珚η的可控性。     

Preparation and Characterization of Polymer Core Shell Latex Particles

Stable core‐shell latex was synthesized by semicontinuous seeded emulsion polymerization with core monomers consisting of styrene (St), butyl acrylate (BA), and shell monomers consisting of methyl methacrylate (MMA), eutyl acrylate (EA), and methacrylic acid (MAA). The effects of compound emulsifier amount, mass ratio of anionic/nonionic emulsifier, and initiator amount on latex performance were investigated. By particle size analysis and transmission electron microscopy (TEM) observation, results suggest that final latex particles have clearly core shell structures.     

PMMA-PAN核壳结构复合乳胶的制备与表征

采用疏水引发剂引发的半连续无皂乳液聚合法,合成了Z均流体力学直径约70nm的聚甲基丙烯酸甲酯(PMMA)纳米乳胶。以PMMA纳米乳胶为种子,采用疏水引发剂引发的种子乳液聚合法,制备了PMMA-聚丙烯腈(PAN)核壳结构复合乳胶。采用动态光散射、傅里叶红外光谱、扫描电镜和透射电镜表征了各种乳胶粒的组成、尺寸、结构和微观形态。研究了反应温度、单体用量和表面活性剂用量对PMMA-PAN复合乳胶粒的结构和形态的影响。结果表明:PMMAPAN复合乳胶粒为核壳结构,其壳层厚度可通过改变单体用量进行调整。     

FTIR Study on the Thermal Ageing of Chlorinated Natural Rubber from Latex

Chlorinated Natural Rubber (CNR) which has good properties of film forming, corrosion-resisting, anti-leakage and anti-combustion and is broadly used in the production of ship paint, container paint,corrosion-resistant paint, adhesive and additive in ink is prepared by the chlorinated modification of NR through solution or latex process. Because of the defects of high equipment investment and cost, environmental hazards and doing harm to workers' health, many countries have prohibited from producing CNR through tetrachloromethane solution process, so the latex process has good prospects in widespread application. There are many reports on the preparation structure and chlorinated mechanism of CNR.But the reports on the thermal ageing of CNR from latex are few. In this paper the dynamic thermal ageing of CNR from latex at 25~360℃ was studied by Fourier Transformed Infrared (FTIR) method.     

茜素黄R稀土配合物的合成和抗菌活性研究

合成了10种茜素黄R的稀土配合物,通过其元素分析、红外光谱、紫外光谱、核磁共振氢谱、热谱的分析,确定它们的组成为 Na [REL2]*2H2O (RE=La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, NaHL=茜素黄R).抗菌活性研究表明,配合物有较强的抗菌活性.     

小粒径无皂阳离子PMMA胶乳粒子的制备与表征

采用溶剂热法,以AIBA为引发剂制得小粒径无皂阳离子PMMA胶乳纳米粒子。讨论了单体用量、引发剂用量和反应温度对胶乳粒径及乳液的粒径分布的影响;用^1H—NMR、TEM、FTIR、GPC、DTA等对聚合物进行了表征。结果表明：采用溶剂热法制得的无皂阳离子胶乳粒子粒径约为35nm,分散均匀;随着温度的升高,粒径逐渐减小;间同、无规、全同立构的相对含量分别为：55．3％、37．8％、6．9％;乳液的抗电解质稳定性好。     

Radiation Graft Copolymerization of a Mixture of Styrene and n-Butyl Acrylate on Natural Rubber Latex

The radiation graft copolymerization of a mixture of styrene (St) and n-butyl acrylate (NBA) monomers on natural rubber (NR) latex has been studied. An irradiation dose of about 18 kGy was needed to attain a conversion of about 80%. The tensile strength of the grafted NR film increases with increasing irradiation dose. A film tensile strength of about 155 kg/cm² was attained by irradiation of a mixture of St, NBA, and NR latex with a dose of about 14 kGy. At low concentrations of monomer in the latex, the Mooney viscosity of the film increases with increasing irradiation dose. At higher monomer concentration, grafting and homopolymerization proceed more favorably than crosslinking, and thus the Mooney viscosity decreases with increasing dose. Thermal analysis of the film showed that the grafted NR was more heat resistant than ungrafted NR.     

Effect of Deproteinized Methods on the Proteins and Properties of Natural Rubber Latex during Storage

Summary: Three different methods of deproteinization, i.e. saponification, surfactant washing and enzymatic treatment were employed to unravel the effect of deproteinized on the properties of natural rubber (NR) latex. The cleavage of proteins in NR latex was found to proceed with concomitant formation of low molecular weight polypeptides. This results in a lowering in gel formation of the enzyme-treated latex, indicating modification of the remaining proteins at the rubber chain-end. Washing NR latex with surfactant would efficiently reduce and remove proteins from NR latex particles through denaturation and transferring them to the serum phase. The relatively stable gel formed during storage of surfactant-washed NR latex is an indication of the absence of branch formation of proteins at the rubber molecule terminal. Saponification by strong alkali would hydrolyze the proteins and phospholipids adsorbed on the latex particle surface. The reason of the significantly higher gel formed in saponified NR latex is still not clear. The present study shows that deproteinization treatments result in modification of the proteins at the surface of NR latex particles and also those freely-suspended in the serum. The cleavage or the denaturation of the rubber proteins during purification by washing has a profound effect on the properties of the deproteinized NR latex upon storage, in particular the thermal oxidative aging properties of the rubber obtained.