细乳液聚合制备纳米SiO2／含氟丙烯酸酯复合乳液及其性能研究

采用溶胶-凝胶法,以正硅酸乙酯为前驱物,在丙烯酸酯单体为油相介质中原位生成纳米SiO2粒子,并通过细乳液聚合,制备出纳米Si02／含氟丙烯酸酯复合乳液。研究了含氟单体和SiO2的用量对复合乳胶膜性能的影响,并采用FT-IR,DSL等分析手段对产物进行了表征。结果表明：该乳液具有良好的稳定性,粒径分布较窄。当（甲基丙烯酸十二氟庚酯）FA与SiO2的用量分别为6％和5．5％时,乳胶膜表现出良好的疏水性能,对水的接触角达到了102．7°,吸水性降低到6．9％。     

两性可聚合型丙烯酸酯单体的合成及应用

以甲基丙烯酸二甲氨基乙酯(DM)和氯乙酸钠为原料进行季铵化反应,合成一类新型的两性可聚合型丙烯酸酯单体。考察了季铵化反应时间、温度等因素对单体合成的影响,用混合指示剂两相滴定法测定反应转化率,同时用红外光谱和核磁波谱对产物结构进行了分析。结果表明:以水为溶剂,DM与ClCH2COONa的物质的量比为1∶1.05,在70℃下,反应7h,叔胺转化率可达93.97%。用上述自制单体制备高分子乳化剂,将其用于乳液聚合,制得性能优良的阳离子乳液和阴离子乳液。     

水溶性单体共聚法制备无皂苯丙乳液的研究

以苯乙烯(St)、丙烯酸(AA)、甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为共聚单体,制备了无皂苯丙乳液;然后以AA含量、中和度、引发剂含量和软/硬单体配比等为试验因素,以乳液稳定性和粒径为考核指标,采用单因素试验法优选出制备无皂苯丙乳液的最佳工艺条件。结果表明:当w(引发剂)=1.2%和w(AA)=4.5%(均相对于单体总质量而言)、中和度为0.8、m(BA)∶m(St+MMA)=4∶6和反应温度为78℃时,可制得粒径为纳米级的高固含量稳定乳液。     

Synthesis and Characterization of New Diisocyanate-Based Polyurethane Cationomers

New diisocyanates, which contain tertiary nitrogen, have been prepared and used in the preparation of polyurethane cationomers. The ionomers were synthesized from commercial diisocyanates (toluene diisocyanate or hexamethylene diisocyanate) as well as from new diisocyanates [N,N′-bis(m- or p-isocyanato-phenyl)pyromellitic diimide] with polypropylene glycol, chain extended with 1,4-butanediol and/or N-methyldiethanolamine and then quaternized with 1,4-bis(chloromethyl)benzene. The cationomers thus formed were characterized by thermogravimetric analysis and differential scanning calorimetric measurements.     

Influence of unsaturated acid monomer on the morphology of latex particles in the preparation of hollow latex via the alkali post‐treatment

Multistage hydrophilic core/hydrophobic shell latexes containing carboxyl groups were prepared via multistep seeded emulsion copolymerization, and particles with different morphologies were obtained after alkali post‐treatment. Influences of the type and content of unsaturated acid monomer on the polymerization and the particle morphology were investigated based on conductometric titration and TEM observation. Results showed that the hydrophilic core/hydrophobic shell particles could be easily formed using methacrylic acid (MAA) instead of acrylic acid. When MAA was 12.2 wt % in the core latex preparation, only fine pores existed inside the alkali‐treated particles. With MAA increased from 20.0 to 30.0 wt %, the alkali‐treated particle morphology evolved from porous, hollow to collapse structure. When MAA further increased to 40.0 wt %, it was difficult to prepare uniform multistage particles and distinct morphologies including solid, deficient swelling, hollow and collapse structure were coexistent in the alkali‐treated particles. Moreover, the forming mechanism of different morphologies was proposed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PLANTWIDE CONTROL STUDY OF A VINYL ACETATE MONOMER PROCESS DESIGN

ABSTRACT

A simulation of a vinyl acetate monomer (VAM) process design was developed and compared with the work of Luyben and Tyreus (1998 Luyben , M. L. and Tyreus , B. D. ( 1998 ). An industrial design/control study for the vinyl acetate monomer process , Comput. Chem. Eng. , 22 , 867 – 877 . [CSA] [CROSSREF] [Crossref], [Web of Science ®] , [Google Scholar]). Two incremental changes were made to the two main control substructures. Specifically, the two schemes focus on improving the liquid inventory system control and controllability of the azeotropic distillation column. The level control strategy was tested and found to produce a faster response with less oscillatory behavior. Two alternative control techniques for the azeotropic distillation column were tested, a feed-forward model predictive controller and a static feed-forward ratio controller. The model predictive controller results illustrated the large difference between the water composition analyzer sample time and the controller step size. The static feed-forward ratio controller showed excellent disturbance rejection of large feed flow variations to the azeotropic distillation column. Simulation results are presented to illustrate the effectiveness of the new control strategies.     

3种燕尾形双子表面活性剂的合成及其表面活性

设计合成了3种基于五苯基苯骨架结构的苝二酰亚胺衍生物n-PDI(n 2,3,4)双子表面活性剂,利用红外光谱仪、核磁共振氢谱仪、热重分析仪,对所合成的3种目标产物结构进行表征与确认,它们的分解温度均在200℃以上。研究了3种双子表面活性剂表面活性参数和热力学参数,结果表明双子表面活性剂分子在水溶液中形成胶束和在气-液界面处的吸附过程是自发的;且双子表面活性剂分子形成胶束的过程易于进行;随温度的升高ΔG_mic^?、ΔH_mic^?、ΔS_mic^?均减小,表明ΔH_mic^?对ΔG_mic^?的贡献有增大趋势,ΔS_mic^?对ΔG_mic^?的贡献有下降趋势,即胶束化过程为熵驱动力在减小而焓驱动力在增大的过程。由SEM测试表明双子表面活性剂能有效吸附在锌电极表面,对其具有缓蚀作用。     

茂金属线形低密度聚乙烯树脂结构性能分析

分析了4种薄膜用线形低密度茂金属聚乙烯(PE-mLLD)及独山子石化生产的线形低密度聚乙烯(PE-LLD)的基本物性指标、热力学性能、凝聚态结构、相对分子质量及其分布、分子链结构及流变性能。结果表明,Exxon Mobile公司的3个PE-mLLD样品均采用己烯共聚,样品具有两种结构,相对分子质量分布较窄的PE-mLLD分子链规整性较好,加工性能较差,但力学性能优于PE-LLD;相对分子质量分布宽的PE-mLLD分子链结构中支化点较多,加工性能较好;DOW公司的样品采用辛烯作为共聚单体,相对分子质量分布较宽,加工性能及力学性能综合表现较好。     

江西某铅锌矿石工艺矿物学研究

江西某铅锌矿在现采矿境界下部发现较大新矿体,为确定新探明资源的合理开发利用工艺,对新探明资源进行了工艺矿物学研究。结果表明：该矿石中矿物种类复杂,有用元素主要有铅、锌、银、金等,主要铅、锌、银矿物有方铅矿、闪锌矿、硫锑铅银矿、硫锑铜银矿。铅锌矿物嵌布特征复杂,共生关系密切,受构造应力作用破坏,闪锌矿碎裂成碎粒,被黄铁矿、方解石等胶结;银矿物在方铅矿中呈蠕虫状、微脉状分布。方铅矿、闪锌矿均为极不等粒嵌布,矿石属难解离、难分选铅锌矿石。最后指出了选矿试验研究过程中应重视的几个问题。     

弹性体高聚物/多官能团单体体系的辐射交联密度

多官能团不饱和单体(Polyfunctional monomer,PFM)是辐射交联应用的重要添加剂。辐照配有PFM的弹性体高聚物时,所产生的自由基首先形成于高分子主链上,然后引发PFM分子中双键的链式聚合反应,从而产生特殊的、对高分子链具有交联作用的接枝链。基于这一简化的敏化辐射交联模型,并结合其它必要的假设条件,推导出交联密度(q)随吸收剂量(D)与单体用量(C0)间变化的关系式。对文献数据的分析结果表明,乙烯-丙烯共聚物(EPR)、顺式-1,4-聚异戊二烯(IR)、聚氯丁二烯(CR)以及丁二烯-苯乙烯共聚物(SBR)等弹性体的q与D、q与C0之间以及IR的q与I／√Ⅰ之间皆具有良好的线性关系。