聚(苯乙烯-环氧乙烷)嵌段大单体的合成、表征及其共聚合的研究

以异丙基苯钾(n-Cumyl potassium)作引发剂,α-甲基丙烯酰氯为终止剂,用阴离子聚合方法合成了一系列不同分子量、不同组成的新型聚(苯乙烯-环氧乙烷)(疏水-亲水型)嵌段大单体[Poly(St-b-Eo)-MA magromer]。用红外光谱及核磁共振进行了鉴定并测定了它的数均官能度(?)_n,对大单体与苯乙烯、甲基丙烯酸甲酯和甲基丙烯酸在不同条件下的共聚反应也进行了研究。发现反应条件对大单体和烯类单体的共聚速率均有很大影响。     

小鼠阴道内注入高分子聚合物HFMC的避孕实验研究

高分子聚合物HFMC是一种良好的组织相容性材料,作者用5％HFMC一次性注入小鼠阴道0.8ml,通过交配实验,观察其避孕效果。结果表明:小鼠应用HFMC后可延迟自然复孕至分娩时间112～118天,与对照组30天相比,差异十分显著(P<0.001);人工复孕的分娩时间与对照组相比,无显著性差异(P>0.05)。     

含聚二甲基硅氧烷侧链的丙烯酸酯共聚物的研究

采用含活性基团的聚二甲基硅氧烷与丙烯酸酯进行自由基共聚合，合成了自聚二甲基硅氧烷侧链的丙烯酸酯共聚物。采用ＩＲ，＾１Ｈ－ＮＭＲ，ＧＰＣ等分析方法对共聚物结构和组成进行了表征。通过接触角和Ｘ－射线光电子能谱对共聚物的表面性能和表面组成进行了研究，并通过粘接性能和破坏面形貌对共聚物与金属铝材和加成型硅橡胶的粘接性进行了探讨。     

A new biodegradable pasty-type copolymer of l-lactic acid and δ-valerolactone with relatively low molecular weight for application in drug delivery systems

Copolymers of l-lactic acid (LA) and δ-valerolactone (VL) with a number-average molecular weight of 1500–2600 were developed as biodegradable carriers for drug delivery. Copolymers were synthesized by direct copolycondensation in the absence of a catalyst. Depending on the mol% of l-lactic acid residues, three different morphologies are obtained: solid state (100-80 mol%), pasty state (70-30 mol%), and waxy state (15-0 mol%). The degradation of the copolymer was markedly influenced by Rhizopus delemer lipase. The rate of degradation of the pasty copolymer in the presence of the lipase is much faster than that for the solid or the waxy Copolymers. A nitrogen mustard derivative of estradiol-17β, Estramustine, was incorporated into a pasty-type copoly(LA/VL, 70/30 mol%) with . The system was completely degraded in vivo (rat) 5 weeks after insertion. A pharmacological effect on the prostates of rats was observed during a period of 5 weeks.     

医用316L不锈钢表面酸预处理工艺研究

研究酸洗预处理对高分子涂层在不锈钢表面粘附强度和浸润性的影响，利用SEM、AFM、RA-IR及接触角测试等技术分析了316L不锈钢表面经不同工艺酸处理前后基体表面微结构、化学状态及润湿性的变化。结果表明，适当的酸处理能显著提高聚乙烯一乙烯醇共聚物(EVAL)涂层在316L不锈钢表面的附着力及它在金属表面的浸润性。     

交联PBA／SAN核—壳乳液接枝共聚研究

ABS是一种性能优异的树脂,但由于橡胶相含有双键而耐候耐热性差,本文试图以交联的聚丙烯酸丁酯为核,合成PBA/SAN核-壳乳液接枝共聚物。考察了核-壳乳液接枝共聚物的定量组成和微观结构。结果表明:接枝物组成近似于其乳液恒比组成;接枝率、接枝效率、分子量和接枝层,壳层厚度随聚合过程参数的改变而呈规律性变化,损耗正切峰表明在种子聚合物相中存在SAN聚合物的微相区。     

丙烯酸基蓖麻油氨基甲酸酯齐聚物的合成和表征

合成和表征了丙烯酸基蓖麻油氨基甲酸酯齐聚物(VTPU)。证明:2,4-甲苯二异氰酸酯(2,4-TDI)与丙烯酸羟乙酯(HEA)封端反应生成丙烯酸基单异氰酸酯(IPT)为二级反应。同样,ITP与蓖麻油(CAO)扩链反应亦为二级。通过对缩合反应速率常数和表观活化能的研究表明:VTPU的结构主要由2,4-TDI中对位和邻位二异氰酸基的活性差异所控制,而齐聚物表观粘度与二异氰酸酯的结构规整性有关。动态粘弹谱测试表明:当VTPU中硬链段含量为59%时,聚合物呈分相结构,抗张强度最高为18.2MPa,若增加至67%时,在100.7℃呈现单一转变峰,动态模量因而下降。     

紫外光固化聚二甲基硅氧烷脲撑氨基甲酸甲基丙烯酸酯的研究——Ⅱ亲水疏水共聚网络体系

本文以α、ω-二氨丙基封端的聚二甲基硅氧烷、甲苯二异氰酸酯、甲基两烯酸羟乙酯为原料,合成了甲基丙烯酸酯封端的聚二甲基硅氧烷聚氨酯。并以此作为反应性低聚物,以甲基丙烯酸羟乙酯为亲水性反应稀释剂,通过紫外光固化,合成了一系列聚硅氧烷含量不同的共聚网络。应用红外光谱、凝胶含量测定、热分析、动态力学性能、吸水性实验等方法,对它们的固化程度、亲水疏水性能进行了研究。结果表明:体系中存在着两相结构,增加稀释剂的含量,材料的吸水性增加。通过调节疏水性的聚二甲基硅氧烷和亲水性的甲基丙烯酸羟乙酯的含量可改变体系的亲水疏水平衡。     

Evaluation of respiratory effects of thermal decomposition products following single and repeated exposures of guinea pigs

Groups of guinea pigs were exposed to the thermal decomposition products (TDP) released from acrylonitrile butadiene styrene (ABS), polypropylene-polyethylene copolymer (CP), polypropylene homopolymer (HP), or plasticized polyvinyl chloride (PVC). In single 50-min exposures to the TDP, guinea pigs exhibited sensory irritation, coughing, and airways constriction. Significant decreases in respiratory frequency (f) occurred during TDP exposure which were magnified during CO₂ challenge conducted immediately post-exposure. For each resin, it was possible to demonstrate a linear relationship between the logarithm of heated mass and the percent decrease in f during CO₂ challenge. From these relationships, the mass of each resin producing a 50% decrease in f during CO₂ challenge (RD₅₀ masses of 2744, 25.2, 16.0, and 6.7 g were obtained for ABS, CP, HP, and PVC, respectively. Thus, the relative potency of their TDP was PVC > CP ≈ HP ≫ ABS. Using the RDC₅₀ mass of each resin, guinea pigs were exposed to TDP for 50 min/day on 5 consecutive days. These repeated exposures also resulted in sensory irritation, coughing, and airways constriction. However, deaths occurred during exposures, and there was evidence of cumulative respiratory effects, and slower recoveries among survivors. Data obtained in guinea pigs were compared to a previous study with mice exposed to the TDP of the same four resins (Schaper et al. 1994). On the basis of heated mass, mice were 20 500 times more sensitive to the acute respiratory effects of TDP than guinea pigs. Thus, the exposure limits of 0.63, 0.11, 0.08, and 0.35 mg/mg³ proposed by Schaper et al. (1994) on the basis of particulates released from ABS, CP, HP and PVC should prevent not only irritation, but also possible couphing, and airways constriction in workers. Received: 14 June 1994/Accepted: 18 October 1994     

聚四氢呋喃聚乳酸共聚物C4对眼组织毒性的实验研究

目的研究聚四氢呋喃聚乳酸共聚物(C4)对眼组织的毒性。方法将聚四氢呋喃聚乳酸共聚物分别置入兔眼玻璃体腔和前房内,定期进行临床观察和视网膜电图检查,6个月后摘除眼球行病理观察。结果聚四氢呋喃聚乳酸共聚物在兔眼玻璃体腔内(168.3±12.6)d完全降解,在前房内(136.5±9.6)d完全降解,视网膜电图正常,眼组织病理观察无异常,兔眼压于手术后第3d及第120d左右两次出现升高。聚合物直接接触角膜内皮1.5个月后内皮细胞消失。结论聚四氢呋喃聚乳酸共聚物对视网膜、晶状体无明显毒性,但不能直接接触角膜内皮。