氯丁橡胶接枝甲基丙烯酸丁酯的热降解动力学

用热重法和微商热重法研究了甲基丙烯酸丁酯与氯丁橡胶的接枝共聚物(CR-g-BMA)的热降解过程。结果表明,该接枝共聚物热降解过程分3个温度范围完成,第1热降解温度为553~653 K;第2热降解温度为653~793 K;第3热降解温度大于793 K,其中第3热降解温度的终止温度明显受升温速率的影响。CR-g-BMA的第1温度范围热分解过程符合Avrami-Erofeev降解机理,即随机成核和随后生成机理,热分解过程平均活化能为234.9 kJ/mol;对于热降解的积分机理函数,其频率因子的自然对数为33.48;对于热降解的微分机理函数,其频率因子的自然对数为48.90。     

新型α-二亚胺中性镍催化剂的合成及催化甲基丙烯酸甲酯(MMA)本体聚合

2,6-二异丙基苯胺经硝化和Schiff碱缩合反应,生成的α-二亚胺配体与无水氯化镍反应制备了中性镍配合物.用FTIR、1H-NMR对中间产物及配合物进行了表征.在甲基铝氧烷(MAO)的助催化作用下,研究了以镍二亚胺为主催化剂对甲基丙烯酸甲酯(MMA)聚合反应的影响因素,考察了聚合温度、n(Al)/n(Ni)值(摩尔比)、聚合时间、n(MMA)/n(Cat)值(摩尔比)等因素对聚合反应的影响,得到的最佳聚合反应条件是:聚合温度为60℃,聚合时间为15h,n(Al)/n(Ni)为600,n(MMA)/n(Cat)为1000.最佳聚合条件下,MMA单体的转化率为65.5%,聚合物的相对分子质量为8.26×104.     

甲基丙烯酸-3-三甲氧基硅丙酯的水解-缩合反应速率常数

在甲基丙烯酸-3-三甲氧基硅丙酯（MPS）和苯乙烯的乳液共聚合反应中,MPS与水接触时其SiOR基团会发生水解缩合反应,其反应速率对乳液体系的稳定有很大的影响,而且所得产物的杂化结构也由SiOR基团的水解缩合反应速率决定.通过²⁹Si核磁共振谱,测定了不同pH值下MPS的水解-缩合速率常数.发现MPS的水解速率常数在pH=7时最小,无论是在酸性条件还是碱性条件都使其迅速增大.而MPS的缩合速率常数则在pH=4时达到最小,而在相对较高pH值和更低的pH值时,其缩合速率常数也都迅速增大.并得到了不同pH值时水解-缩合速率常数估算式.为进一步研究MPS乳液聚合的过程机理、反应过程动力学模型的求解以及通过模型对反应结果的预测提供了依据和基础数据.     

丙烯酸粉末涂料的制备及其性能研究

主要研究了GMA型丙烯酸透明粉末涂料的制备工艺和涂料的测试性能,并将其与纯聚酯透明粉末涂料进行了比较.结果表明,虽然GMA型丙烯酸透明粉末涂料在工业生产过程中的操作要求稍高,价格稍贵,但它是一种高质量的粉末涂料.     

自交联型水性聚丙烯酸酯分散体的制备及其性能

以甲基丙烯酸甲酯(MMA)为硬单体、丙烯酸丁酯(BA)为软单体、丙烯酸(AA)为功能单体、甲基丙烯酸乙酰乙酰氧基乙酯(AAEM)为交联单体、过氧化苯甲酸叔丁酯为引发剂、乙二醇丁醚为溶剂,通过自由基溶液聚合经转相方式制备了自交联型丙烯酸酯分散体,该分散体在烘烤条件下不需要外加交联剂即可发生自交联反应.研究了丙烯酸、甲基丙...     

The critical organic modifier aliphatic tail length for the formation of poly(methyl methacrylate)-montmorillonite nanocomposites

In this article, we report the influence of organic modifier structure (alkyl chain length C8-C20, single vs ditallow) and thereby, the effect of hydrophobicity on the structure, thermal and mechanical properties of poly(methyl methacrylate) (PMMA)-clay hybrids. Melt processed PMMA-clay hybrids were characterized using wide-angle X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. The organoclays having an alkyl chain length of more than 12 CH₂ groups resulted in the formation of nanocomposites. The glass transition temperature (T_g) of PMMA increased in the presence of clay. The mean-field lattice model was used to predict the free energy for nanocomposite formation, which showed a reasonable match with the experimental results and provided a general guideline for the proper selection of polymer and organoclay (ie, organic modifier) to obtain nanocomposite. Tensile modulus showed maximum improvement of 58% for the nanocomposites compared to 9% improvement for the composites. Tensile modulus increased with increases in the alkyl chain length of the organic modifier and clay loading. The level of improvement for the tensile properties of nanocomposites prepared from primary and secondary ammonium-modified clay is the same as that obtained with the commercial organoclays.     

Improved compatibility of PET/HDPE blend by using GMA grafted thermoplastic elastomer

ABSTRACT

Herein, graft-modified ethylene-1-octene copolymer (POE-g-GMA) and styrene-butadiene-styrene triblock copolymer (SBS-g-GMA) were found to be excellent reactive compatibilizers for immiscible poly(ethylene terephthalate) (PET)/high-density polyethylene (HDPE) blends via in-situ reaction compatibilization. With increase in compatibilizer amount, uniform phase morphology was observed in all the blends. Thus, exhibiting enhanced mechanical properties, especially, the notched Izod impact strength. In comparison with SBS-g-GMA, compatibilizer POE-g-GMA demonstrated greater impact on the compatibility. The addition of 15% POE-g-GMA produced blends with best mechanical properties. Besides, both POE-g-GMA and SBS-g-GMA enhanced the melt viscosity of PET/HDPE blends.     

自交联水性聚氨酯-含氟丙烯酸酯乳液的制备及研究

以异佛尔酮二异氰酸酯(IPDI)、聚碳酸酯二醇(PCDL)、二羟甲基丁酸(DMBA)、1,4-丁二醇(BDO)、甲基丙烯酸羟乙酯(HEMA)为原料合成了双键封端的聚氨酯预聚体;以N-羟乙基丙烯酰胺(HEAA)作交联剂,配合甲基丙烯酸六氟丁酯(HFBMA)等单体进行乳液共聚,制备了自交联水性聚氨酯-含氟丙烯酸酯(FPUA)乳液。研究了HFBMA和HEAA用量对膜耐水性、热性能以及力学性能的影响。结果表明:PUA乳液的耐水性和疏水性随HFBMA用量的增加而增加;随着HEAA用量增加,胶膜的热稳定性增加,拉伸强度增加,伸长率下降;当胶膜中HFBMA质量分数为12%,且HEAA质量分数为2.6%时,乳液的粒径为128 nm,乳液的稳定性较好;胶膜的水接触角为107.6°,吸水率为4.5%,拉伸强度为25.6 MPa,断裂伸长率为268%,10%热失重温度299.6℃。     

抗冲ACR树脂的合成及其性能评价

采用种子乳液聚合法,以丙烯酸丁酯为核层单体、甲基丙烯酸甲酯为壳层单体、甲基丙烯酸烯丙酯为交联剂制备了抗冲ACR树脂。考察了不同加料方式对ACR乳液粒径及对PVC冲击性能的影响,结果表明:连续滴加方式可实现乳液粒径的稳定控制,并能得到性能优异的抗冲ACR树脂。     

累托石的有机改性及其对凝胶聚合物电解质的影响

用十二烷基二甲基苄基氯化铵改性天然黏土累托石,得到有机改性累托石(organic modified rectorite,OREC),再用OREC改性凝胶聚合物电解质.对OREC进行红外、X射线衍射、偏光显微分析,并对OREC改性的凝胶聚合物电解质体系的X射线衍射结果、离子电导率及热性能进行了分析.结果表明:OREC能作为改性剂用在凝胶聚合物电解质中,在凝胶电解质中达到完全解离,能提高电解质的离子电导率,且改性电解质的玻璃化转变温度随OREC添加量的增加而增大,热稳定性提高.