不同改性蒙脱土对聚丙烯/蒙脱土纳米复合材料性能的影响

采用四种不同的改性剂对蒙脱土进行处理,在三单体固相接枝聚丙烯作用下,将聚丙烯与四种改性蒙脱土进行复合,制备聚丙烯/蒙脱土纳米复合材料,研究了四种复合材料的结构与力学性能.结果表明,经十六烷基三甲基氯化胺或自制的长碳链带有反应基团的不饱和季胺盐改性的蒙脱土与聚丙烯复合可制备性能优良的纳米复合材料,从力学性能来说,十六烷基三甲基氯化铵改性蒙脱土的效果最好.     

研究与述评

201208092碳纳米管-PMMA杂化涂料的机械性能:表面化学的重要性[刊,英]/Mammeri,Fayna等//RSC Advance.-2012,2(6).-2462~2468碳纳米管(CNTs)在一般有机溶剂和有机单体中较差的混溶性需要通过适当的功能基团(活性基团或非活性基团)加以改性,以便将碳纳米管与热塑性塑料聚合物相容。本文主要通过以下两个阶段研究了CNTs的表面功能对与     

油酸甲酯合成反应的热力学性质分析

采用Joback基团贡献法、Yoneda基团贡献法及Tyagi方程估算了无催化"两步法"合成油酸甲酯反应体系中油酸、油酰氯、油酸甲酯等物质的热力学数据,并结合可查取的物性实验数据,得到了该反应体系反应焓变ΔrHm、反应熵变ΔrSm、反应吉布斯自由能变ΔrGm及反应平衡常数K。结果表明:标准状态下酰氯化为吸热反应,且单独存在时较难进行,醇解为放热反应,且反应可进行完全。通过分析各热力学函数数值特点,结合整个两步反应的始末态热力学数据,依据近似原则和勒夏特列原理平衡移动原理,可以得出酰氯化反应在适当条件下是可正常进行的,且实际实验现象对此进行了验证。     

Research progress on chemical modification of silk fibroin and its applications北大核心CSCD

Mulberry silk is composed of the two major parts of two triangle-like silk fibroin fibers and sericin covering the fibers and a few lipids. After removing the sericin on the raw silk what is left is the silk fibroin fiber. Silk fibroin is the main part of silk accounting for about 75% of the total weight. Silk fibroin contains 18 natural amino acids such as glycine Gly alanine Ala serine Ser serine aspartic acid Asp and tyrosine Tyr . The secondary structure of silk fibroin has three main conformations α-helix β-fold and random coil. Under certain conditions the three conformations can transform into each other and change the mechanical properties of the silk fibroin material. Silk fibroin extracted from silk fiber is a natural polymer with biocompatibility and biodegradability. It can be further processed into different forms of materials nanoparticles films hydrogels sponges etc. It has been applied in many fields such as biomedicine and cosmetics. In order to meet the needs of different fields researchers have conducted further chemical modification treatment based on the original excellent properties of silk fibroin. Meanwhile the active groups on various amino acid residues in silk fibroin also provide chemical reaction sites for the chemical modification of silk fibroin. The chemical modification methods of silk fibroin mainly include amino acid residue modification macromolecular grafting modification and crosslinking reaction modification. Among them amino acid residue modification can modify protein amino acid residues by chemical reagents and some groups can be introduced into the side chains of silk fibroin macromolecules. Grafting modification of silk fibroin macromolecules is one of the main means to bind functional compounds to silk fibroin macromolecular chains. The properties of grafted silk fibroin are affected by the type and grafting rate of the grafts. The chemical crosslinking reaction modification of silk fibroin macromolecules is to make the macromolecular chains connected by covalent bonds and form a network structure by means of crosslinking agents enzymes or ultraviolet irradiation. The cross-linking reaction can not only form covalent bonds within and between the molecular chains of silk fibroin thus changing its structural properties and improving its stability but be used to form covalent bonds with other polymers. At present the chemical modification of silk fibroin is mainly applied in the fields of silk textiles biomedicine and environmental science. In the field of silk textiles graft copolymerization modification of vinyl and other monomers crosslinking agent modification and other methods are used to overcome the shortcomings of silk like being easy to wrinkle. The graft modified monomers mainly include ethylene methacrylate and methylacrylamide. The active groups on crosslinking agents such as polycarboxylic acid / anhydride and epoxide are covalently combined with carboxyl hydroxyl and amino groups on macromolecules of silk fibroin to improve the wrinkle resistance of silk fabrics. In the field of biomedicine silk fibroin materials with appropriate chemical modification have better biological activity drug delivery ability antimicrobial properties and mechanical properties. The optimization of these properties enables silk fibroin materials to show great potential in drug control delivery tissue regeneration and wound repair. The applied research in the field of environmental science mainly focuses on the adsorption separation and catalysis of impurities in water. Therefore the modification of amino acid residues grafting and cross-linking of protein macromolecules can change some important properties of silk fibroin and meet the requirements of various applications and functionalization of silk fibroin. In many fields of chemical modification and application of silk fibroin protein fruitful results have been achieved which has laid a good foundation for the further development of related fields and also shows that the chemical modification of silk fibroin material has great potential and application prospects. However there are still some problems that need to be overcome and further improved in the current chemical modification methods such as mild modification conditions and accurate adjustment of the degree of modification which will be the research direction of related fields in the future. © 2022 Authors. All rights reserved.     

含有多种活性基团的腐植酸有机肥及其制备方法

<正>申请(专利权)人:上海禾绿生物有机肥有限公司申请日期:2013.02.05申请(专利)号:CN201310045904主分类号:C09K101/00;C09K17/40本发明提供了一种含有多种活性基团的腐植酸有机肥,其特征在于,由秸秆10~15重量份、废菌苞20~25重量份、鸡粪10~15重量份、猪粪10~15重量份、牛粪30~40重量份和活性腐植酸5~10重     

对苯二甲酸催化加氢制备1,4-环己烷二甲酸的热力学分析

采用Constantinou-Gani基团贡献法和Rozicka-Domalski基团贡献法计算了对苯二甲酸(TA)加氢制备1,4-环己烷二甲酸(CHDA)过程中可能涉及的主副产物的标准摩尔生成焓、标准摩尔蒸发焓和定压热容。在373.15~573.15 K的温度下,分别计算了TA加氢反应体系中各反应的焓变、Gibbs自由能变和平衡常数。计算结果表明,在373.15~573.15 K温度范围内,TA加氢反应以苯环加氢反应和脱羧基反应为主。TA加氢生成CHDA的反应是放热反应,低温有利于该反应的进行,而TA脱羧基生成苯甲酸的反应是吸热反应,高温有利于该反应的进行。但因低温不利于TA的溶解,综合考虑,选择TA加氢制备CHDA的反应温度为493.15~523.15 K较适宜。     

1,3-二氯-2-丙醇脱氯化氢制备环氧氯丙烷热力学分析

利用Benson基团贡献法计算了1,3-二氯-2-丙醇脱氯化氢制备环氧氯丙烷反应中1,3-二氯-2-丙醇和环氧氯丙烷的气态标准熵、等压热容。结合其他已知热力学数据,计算了该反应的焓变、熵变、吉布斯自由能变、反应平衡常数以及平衡转化率。结果表明:该反应为吸热反应,当温度高于970K时,脱氯化氢反应在热力学上是可行的,反应的适宜温度为970K。     

高分子化学课程教学思考

高分子化学是材料化学类专业重要的专业基础课,有较强的理论性。文章针对高分子化学中的一些重点难点问题,如等活性理论、邻近基团效应和自由基等进行了梳理和总结,为了促使学生能够更好的理解,在教学方法上进行了由浅入深的解释,主要介绍了本人的理解和教学方法上的感受,以供参考。     

烷基胺羰基化反应的热力学计算与分析

利用基团贡献法估算了烷基胺类化合物与CO羰基化反应生成N-烷基甲酰胺的标准生成焓、标准熵和摩尔定压热容,对反应体系的热力学性质进行计算,得到不同反应温度下的反应焓变、吉布斯自由能变以及反应平衡常数等热力学数据。分析了反应的方向与限度,考察了温度对反应焓变、吉布斯自由能变和反应平衡常数的影响,比较了热力学数据随反应物分子结构的变化规律。结果表明:在323 K到473 K的温度区间内,文中涉及的烷基胺羰基化反应均为放热反应,随反应温度的升高,反应由自发向右进行转变为非自发反应。烷基胺N原子上取代基个数和结构的不同对反应热、反应方向与限度均产生影响。     

苯酚与异丙醇烷基化合成异丙基苯酚的热力学和动力学

基于Benson基团贡献法研究苯酚与异丙醇烷基化反应过程,确定了主、副反应的反应热、平衡常数及平衡转化率,得到反映热力学性质的反应方程式并建立反应的网络结构,为该体系的工艺设计提供热力学依据。在苯酚与异丙醇物质的量比为0.5~2.0、温度(513.15~573.15)K、空速8 h-1和催化剂颗粒(40~60)目[相当于粒径(0.45~0.30)mm]条件下进行本征动力学实验。选用幂数型动力学模型,对参数进行估值。用Runge-Kutta法进行数值积分,Simplex法对参数进行优化,F统计法对模型进行检验,最终得到能较好描述反应的本征动力学模型。