PVC-U异型材塑化度的评价

比较了4种评价PVC-U塑化度的方法:目测法简单;溶剂法迅速,容易操作;拉伸法可定量判断,但需要大量样品;DSC法准确、方便。     

用Simha-Somcynsky状态方程改进高分子中溶剂扩散系数模型

将Simha-Somcynsky状态方程和Vrentas-Duda的自由体积理论模型相结合，提出改进的高分子中溶剂扩散系数模型.改进的模型利用状态方程和WLF理论定义的自由体积分数确定扩散过程的有效自由体积，避免原模型中繁琐的黏弹性实验测定.对苯、甲苯、乙苯、氯仿在聚苯乙烯、聚异丁烯和聚醋酸乙烯酯中的扩散系数的计算结果表明，改进模型的预测值与实验值取得较好一致，且自扩散系数的预测精度比原模型高.同时，改进的模型能够反映压力对扩散系数的影响.溶剂扩散系数随外界压强增加而减小，当溶剂浓度较低时，压强的影响非常显著，扩散系数可相差几个数量级.随着溶剂浓度升高，扩散系数接近常压时的扩散系数，压强影响可以忽略.     

Production of propylene glycol fatty acid monoesters by lipase-catalyzed reactions in organic solvents

Fatty acid monoesters of propylene glycol (1,2-propanediol) are good water-in-oil emulsifiers. These esters were synthesized enzymatically to overcome the problems associated with chemical processes. APseudomonas lipase was added to reaction mixtures containing propylene glycol and various acyl donors (fatty acids, fatty acid ethyl esters, fatty acid anhydrides and triglycerides) in organic solvents, and the mixtures were shaken at 30°C. The products were analyzed by gas chromatography. The yield of monoesters was affected by the acyl donors, organic solvents, temperature, water content, pH memory and reaction time. The anhydrous (lyophilized) enzyme and fatty acid anhydrides were best for monoester production. The optimum pH ranges were 4–5 and 8–10. The yields of propylene glycol monolaurate, monomyristate, monopalmitate, monostearate and monooleate with 50 mM fatty acid anhydrides as acyl donors were 97.2, 79.6, 83.7, 89.7 and 93.4 mM, respectively; those with 50 mM fatty acids as acyl donors were 37.3, 28.7, 28.7, 35.3 and 36.2 mM, respectively. The yields of propylene glycol monopalmitate, monostearate and monooleate with 50 mM triglycerides as acyl donors were 87.4, 65.1 and 83.2 mM, respectively.     

Miscibility behavior of blend of polyesteramides of linseed oil and dehydrated castor oil with poly(methacrylic acid)

Blending of two polymers in solution is a simple and cost‐effective technique to improve upon the physical and mechanical properties of the component polymers through synergism. To obtain maximum synergy in their properties, the component polymers should be miscible with each other on molecular scale. Polymer blends of complex physicomechanical properties are being actively investigated. Poly(methacrylic acid) (PMAA), a commercial polymer, yields transparent, hard, brittle, and water‐sensitive films. It has been blended with natural polymers like dextran, collagen, and gelatin to obtain films with improved physical and mechanical characteristics. Polyesteramides, which are easily synthesized from vegetable seeds oil, a sustainable resource, have found application in surface coatings. These oligomeric products do not make free standing films in the ambient condition. The polyesteramides from vegetable seeds oil can be used to obtain blend with PMMA of improved mechanical and water absorption properties. In this study, linseed oil polyesteramide (LOPEA) and dehydrated castor oil polyesteramide (DCPEA), the source oils with different unsaturation in their fatty acid chains, were blended with PMAA through mixing in solution in the ratio DCPEA/LOPEA: PMAA as 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, and 20/80. In the first instance, the miscibility of the two components was investigated in solution by viscosity and ultrasonic measurements and in solid phase through differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Moisture absorption by the blend was also studied. DCPEA and LOPEA show immiscibility with PMAA in solution phase while LOPEA with more unsaturation in the fatty acid chain of the oil was found more immiscible than DCPEA. DCPEA shows a narrow miscibility window in the solid phase while LOPEA was found immiscible with PMAA in the solid phase too. Uptake of moisture was found to be markedly reduced in the blends of DCPEA/LOPEA with PMAA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1367–1374, 2007:     

醇溶剂中TS-1催化丙烯环氧化的本征动力学与反应机理研究

研究了在三种不同醇溶剂(甲醇、异丙醇和仲丁醇)水溶液中TS—l催化丙烯过氧化氢环氧化反应的本征动力学，反应条件为温度30～60℃，丙烯压力0．4-0．6MPa。根据实验现象和各组分在TS-1上的吸附特点建立了该反应的Eley-Rideal机理模型，环氧化反应在吸附态的H2O2分子与游离态的丙烯分子之间进行，表面反应为速度控制步骤。通过实验数据对机理模型进行了参数估值，检验结果表明拟合效果较好，平均偏差在10％以内。最后对过程进行了进一步讨论，为该过程的工业化提供了依据。     

Natural rubber–ethylene‐propylene‐diene rubber covulcanization: Effect of reinforcing fillers

Filled covulcanizates of elastomer blend comprising natural rubber (NR) and ethylene‐propylene‐diene rubber (EPDM) of commercial importance were successfully prepared by using a multifunctional rubber additive; namely, bis(diisopropyl)thiophosphoryl disulfide (DIPDIS). A Two‐stage vulcanization technique further improved the physicochemical properties of the blend vulcanizates by restricting, through the formation of polar rubber bound intermediates, the migration of curative and filler from lower to highly unsaturated rubber. Scanning electron microscopy studies indicate homogeneity and coherency in the morphology of the two‐stage vulcanizates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1001–1010, 2002; DOI 10.1002/app.10361     

相容剂对PE-HD／PET共混合金性能的影响

以乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯三元共聚物（PTW）作为高密度聚乙烯（PE-HD）／聚对苯二甲酸乙二醇酯（PET）共混合金的反应性相容剂，采用熔融挤出法制备了以PE-HD为基体的PE～Hi）／PET、共混合金。通过力学性能和流变性能测试，扫描电镜（SEM）和动态力学分析（DMA）等手段，研究丁PTW对共混合金性能的影响。结果表明：PTW提高了体系的综合性能，当PE-HD／PET配比为90／10，PTW含量在5份时，其缺口冲击强度提高了近400％，拉伸强度和断裂伸长率分别提高了25％和50％，同时改善了共混合金的加工性能。SEM分析表明PTW的加入增大了共混合金的界面相互作用，促进了分散相粒子的细化，从而提高丁体系相容性，DMA测试表明，PTW的加入使PET的玻璃化转变温度向PE—HD的玻璃化转变温度靠近：     

苯乙烯类嵌段共聚物对IR/CR共混物形态结构的影响

考察了苯乙烯类嵌段共聚物对ＩＲ／ＣＲ二元共混物相态结构及粒子尺寸的影响。结果表明，加入苯乙烯类嵌段共聚物可有效改善ＩＲ／ＣＲ共混物的分散状态，在任何组成下均可降低分散相粒子尺寸，促进体系均匀分散，其中苯乙烯－异戊二烯共聚物的效果最为理想，其最佳用量为３～７份。     

改性胶粉/SBR共混胶料的结构性能研究

研究了硫黄、促进剂、改性胶粉用量对胶粉／ＳＢＲ共混胶料性能的影响。结果表明；改性胶粉用量在１０－３５份的范围内．对共混胶料的静态力学性能影响不大：在１０－２２份的范围内对动态压缩疲劳生热影响不大．适当调整基质胶中硫黄、促进剂的用量．有利于降低胶料的动态压缩疲劳生热。扫描电子能谱微区分析的研究表明：由于硫黄的迁移形成了具有特殊结构的界面过渡层．该过渡层是降低动态压缩疲劳生热的关键。     

氨纶干法纺丝介质循环系统的设备和工艺介绍

介绍氨纶干法纺丝技术中纺丝介质 (SM )循环系统的主要设备 ,对循环风压力、风温度和风量控制进行了探讨。严格控制SM循环工艺参数 ,可减少并丝现象。