PPG对聚氨酯树脂耐水性能影响研究

聚氨酯弹性体作为一种高性能弹性体,综合性能优良,制品应用广泛,涉及建材、交通、机械、医疗等诸多领域。在聚氨酯弹性体配方优选方面,重点研究了HDI含量和PPG含量对聚氨酯弹性体拉伸性能和水解稳定性的影响。红外光谱分析表明,随着HDI和PPG含量的减少,形成氢键区域吸收峰强度增强,表明弹性体内形成氢键数量增多。聚氨酯弹性体水解稳定性测试结果表明,HDI含量越高,聚氨酯水解稳定性越差,PPG含量越高,水解稳定性越好。     

聚氨酯／乙炮基酯树脂互穿聚合物网络结构与性能的研究

通过同步法制备了一系列聚氨酯／乙烯基酯树脂互穿聚合物，研究了ＰＵ／ＶＥＲ－ＩＰＮ性能的影响因素。结果表明：随着ＰＵ含量的增加，ＩＰＮ的热稳定性能有一定程度的提高；而ＶＥＲ的含量增加，ＰＵ／ＶＥＲ－ＩＰＮ的剪切强度提高。实验还发现：当ＰＵ／ＶＥＲ－ＩＰＮ为部分相容的多相微区结构时，对增加ＩＰＮ的力学损耗更有利。     

聚氨酯橡胶旱冰轮的研制

聚氨酯橡胶旱冰轮的研制聂玉梅，张枫，刘连顺ＭＡＮＵＦＡＣＴＵＲＥＯＦＰＯＬＹＵＲＥＴＨＡＮＥＲＵＢＢＥＲＲＯＬＬＥＲ１前言聚氨酯橡胶是一种嵌段聚合物，只要改变它的软硬段的组成和比例就可广度改变物理性能，其最大特点是硬度大，弹性好，良好的弹性非塑料可比...     

聚氨酯和苯乙烯—马来酸酐无规共聚物反应性共混研究Ⅱ 共混物力学性能

合成了聚氨酯（ＰＵ）／苯乙烯－马来酸酐无规共聚物（ＲＳＭＡ）共混物,研究了不同条件下ＰＵ／ＲＳＭＡ共混物的力学性能,并对实验结果进行了讨论。     

聚氨酯/乙烯基酯树脂互穿聚合物网络结构与性能的研究

通过同步法制备了一系列聚氨酯／乙烯基酯树脂互穿聚合物（ＰＵ／ＶＥＲ－ＩＰＮ）,研究了ＰＵ／ＶＥＲＩＰＮ性能的影响因素。结果表明：随着ＰＵ含量的增加,ＩＰＮ的热稳定性能有一定程度的提高;而ＶＥＲ的含量增加,ＰＵ／ＶＥＲ－ＩＰＮ的剪切强度提高。实验还发现：当ＰＵ／ＶＥＲ－ＩＰＮ为部分相容的多相微区结构时,对增加ＩＰＮ的力学损耗更有利     

木薯醚化淀粉填充聚氨酯弹性体的力学性能及结构形态的研究

向聚醚型聚氨酯预聚体中分别添加木薯淀粉及其改性的木薯醚化淀粉，再经进一步交联得到了聚氨酯（ＰＵ）弹性体。结果表明，填充６％～３０％（质量）木薯醚化淀汾，对ＰＵ弹性体的力学性能除扯断伸长率外，其他均有明显提高，其热老化稳定性也好。通过化学分析，证实了木薯醚化淀粉与ＰＵ中的异氰酸酯基有化学反应。扫描电镜和Ｘ－射线分析表明，木薯醚化淀粉在ＰＵ中具有良好的分散性和相容性，从而保证了木薯醚化淀粉填充ＰＵ的良     

阻燃耐烧蚀聚氨酯包覆材料的研究

合成了几种类型的以异氰酸基封端的液体预聚物。制备了九种聚氨酯树脂。评价了ＰＵＲ中芳杂环含量及阻燃元含量对产品阻燃性与烧蚀性的贡献。筛选出一种综合较为优良的ＰＵＲ包覆材料。并完成了静止发动机点火实验，效果明显。     

聚氨酯／乙烯基酯树脂互穿聚合物网络的力学性能研究

研究了适用于反应注射成型的乙烯基酯树脂（ＶＥＲ）与聚氨酯（ＰＵ）形成互穿聚合物网络（ＩＰＶ）时，ＶＥＲ中的羟基与异氰酸酯的反应对材料力学性能的影响。实验结果表明，若异氰酸酯的化学计量忽略ＶＥＲ中的羟基，则对所合成的ＰＵ／ＶＥＲＩＰＮ而言，ＰＵ对ＶＥＲ的增韧效果较差；若异氰酸酯的用量考虑ＶＥＲ中的羟基含量，则用碳化二亚胺改性二苯基甲烷二异氰酸合成的ＰＵ／ＶＥＲ（组成比５０／５０）ＩＰＮ的拉伸或冲击强度分别比纯ｐｕ或纯ＶＥＲ网络要高得多，可获得兼具刚性与韧性的材料。在这类ＩＰＮ中添加少量聚醚接枝的ＶＥＲ，可有效地提高材料的拉伸强度。     

增强反应注射成型聚氨酯及其性能研究

以反应注射成型聚氨酯（ＲＩＭ－ＰＵ）为基体树脂，研制了以玻纤增强剂的增强反应注射成型聚氨酯（ＲＲＩＭ－ＰＵ）材料。讨论了原材料及玻纤对ＲＲＩＭ－ＰＵ加工工艺及材料性能的影响。结果表明，以碳化二亚胺改性的异氰酸酯（ＣＭ－ＭＤＩ）和低聚合异氰酸酯改性的异氰酸酯（ＰＡＰＩ）混合物与丙腈－－苯乙烯接枝改性环氧乙烷封端的聚醚二元醇（ＡＰＧ）为主要原料，玻纤长度不大于１．５时，不仅ＲＲＩＭ加工工艺性好，而且Ｒ     

新型单组分松香蔗糖聚氨酯—聚丙烯酸涂料研究

以松香,蔗糖,聚丙烯酸酯及异氰酸酯预聚体等为原料,合成了一种单组分聚氨酯清漆。研究了化学组成对漆膜性能的影响。结果表明,当松香蔗糖聚氨酯（ＡＲＳＰＵ）与聚丙烯酸酯（ＰＡ）共混的质量比为６５／３５,而ＡＲＳＰＵ合成中ＡＲＳ与异氰酸酯预聚体的质量比为６５／３５时,漆膜的耐溶剂性能及硬度较为合适。该清漆快干,耐低温,耐油,耐水,耐酸碱性能良好。     

Dilute acid hydrolysis of lignocellulosics: An application to medium consistency suspensions of hardwoods using a plug flow reactor

A one-stage process for the high temperature rapid dilute acid hydrolysis of hardwoods, to produce simultaneously furfural and fermentable sugars, is described. A continuous plug flow reactor unit designed to hydrolyse medium consistency wood suspensions (up to 13% w/w in solids) has been operated at capacities up to 90 kg/h, with temperatures ranging from 190°C to 240°C and 20-120 s as residence times. The final products, mainly furfural and sugars, have been analyzed using high performance liquid chromatography. Yields of 15 kg of hexoses (30% of the theoretical potential) and 10 kg of furfural (65% of the theoretical potential) for 100 kg of sawdust (dry basis) have been obtained. Two pseudokinetic modeis were used to simulate the pentosan and hexosan acid hydrolysis reactions. A Flowtran Simulation has been conducted resulting in mass and energy balances for an eventual industrial unit.     

Intensifying chitin hydrolysis by adjunct treatments – an overview

Chitin is, after cellulose, the most abundant organic natural polysaccharide on Earth, being synthesized as a dominant component in the exoskeletons of crustaceans, among other sources. In the processing of seafood for human consumption, between 40 and 50% of the total raw material mass is wasted, causing a significant problem for the environment owing to its slow degradation. Efforts to find uses for chitin derivatives, particularly their oligomers, have intensified since these chemicals are highly functional and offer a wide range of applications, especially as antimicrobial agent. As a consequence, some adjunct treatments, either chemical or physical in nature, have been employed to assist acid and enzymatic hydrolysis. This work provides a detailed review of the methods employed to intensify the formation of chitin oligomers, particularly focusing on the adjunct treatments used (microwave, ultrasonication, steam explosion and gamma irradiation), and an evaluation of the yield and characteristics of the oligomers formed. Adjunct treatments are more suitable for enzymatic hydrolysis since these treatments modify the chitin structure, and enhance the hydrolysis rate and yield of the oligomers, under milder reaction conditions. For future research, it would be worth trying pre‐treatments like the application of high‐pressure to chitin in order to lower its crystallinity. © 2017 Society of Chemical Industry     

Imidazoline hydrolysis in alkaline and acidic media—A review

The literature was reviewed for information on imidazoline hydrolysis. Conflicts involving structures and mechanisms of hydrolysis have been found. Researchers also disagree as to the role of water and whether a protonated form of the imidazoline exists. However, there is agreement that the rate of hydrolysis is dependent on pH and temperature.     

改进水解-A~2/O工艺处理城镇污水的试验研究

在A~2/O池前加水解池,并将二沉池出水部分同流到水解池,增加水解反硝化作用,研究改进水解池-A~2/O工艺对处理城镇生活污水的影响情况.试验结果表明,在二沉池到水解池的回流比分别为28%和40%时,系统出水TN质量浓度分别为13.22 mg·L~(-1)和9.61 mg·L~(-1),COD分别为72 mg·L~(-1)和54 mg·L~(-1),TP质量浓度分别为1.9 mg·L~(-1)和1.1 mg·L~(-1),2个工况下出水TN质量浓度均小于15 mg·L~(-1),达到了城镇污水处理厂污染物排放标准(GB18918-2002)一级A标准,满足了试验目的.     

尿素水解方法的简述及展望

综述了现今国内外尿素水解技术的研究现状,对各种水解技术的优点和存在的不足进行了梳理与总结。并展望其发展前景,提出了需进一步研究及解决的问题。     

ETHANOL FROM SOUTHERN HARDWOODS: THE ROLE OF PRESULFONATION IN THE ACID HYDROLYSIS PROCESS

A two-stage acid hydrolysis process is currently used in the production of ethanol from hardwoods. In this process, dilute sulfuric acid in water at high pressure and short residence times hydrolyzes the wood and first stage substrate. The chemical action is particularly impeded in the second stage by the presence of acid condensed lignin.

Presulfonation followed by delignification is proposed using a sulfur dioxide/water sulfuric acid/ethanol treatment step in place of the first stage acid hydrolysis step to alleviate this problem.

Results presented include the effects caused by varying treatment time, sulfur dioxide concentration, temperature and ethanol concentration on the degree of delignification, and, on the recovery of C₅ and C₆ sugars in the hydrolysates. A preliminary economic feasibility analysis is made to determine the impact of improved ethanol yields and lignin by-product values in the production of ethanol from hardwoods.     

厌氧水解的新解读：快速水解和慢速水解

挥发性脂肪酸（VFA）具有可生化性好、附加价值高等优点而得到广泛应用,厌氧消化产VFA是目前学术界的研究热点,但对有机物经过水解后的生物降解性能则少有论及,厌氧发酵过程中的水解产物存在“数量”和“质量”之间的权衡问题。为了进一步提高厌氧发酵过程中微生物对有机物的利用效率,突破水解对厌氧消化的限制性作用,从基质碳源释放快慢及厌氧发酵过程中碳源降解性能不同,本文将厌氧水解分为快速水解和慢速水解,分别阐述了两种水解方式的含义、分类以及优缺点,指出细胞内外碳源的释放速率和释放方式的不同是影响厌氧产酸和生物降解性能的决定性因素。最后指出快速水解与慢速水解相结合的分阶段联合处理方式,是今后厌氧消化产VFA的主要研究方向。     

尿素深度水解装置运行总结

简介了国内、外成熟的尿素工艺冷凝液处理工艺的主要特点,介绍了采用国内立式水解塔处理尿素工艺冷凝液的工艺流程及装置运行情况.实践证明,装置设计是成功的,吨尿素氨耗降低了8 kg,取得了明显的经济效益和环保效益.     

塑料水解稳定剂的研究进展

简述了塑料水解的机理。重点介绍了国内外塑料水解稳定剂的制备及使用情况。比较了不同的塑料水解稳定剂的优势与应用前景。     

二甲基二氯硅烷浓酸与恒沸酸水解方法比较

聚二甲基硅氧烷主要由二甲基二氯硅烷水解制得,介绍了二甲基二氯硅烷水解的两种方法,即浓酸水解法与恒沸酸水解法,以60 kt/a二甲基二氯硅烷水解为例,对两种水解工艺过程的用能、设备投资、占地投资等进行了计算分析。结果表明,浓酸水解方法具有成本低、能耗低、流程短等优点,将逐渐取代恒沸酸水解方法成为聚硅氧烷生产的新的发展趋势。