甲基丙烯酸甲酯—苯乙烯共聚物分子质量的研究

在６０～９０℃温度范围内,以ＡＩＢＮ为引发剂进行了甲基丙烯酸甲酯（ＭＭＡ）－苯乙烯（Ｓｔ）本体自由基共聚合,用粘度法测定了共聚物的分子质量。在转化率０～９５％范围内,研究了聚合温度、引发剂浓度及单体配比对ＭＭＡ－Ｓｔ共聚物分子质量的影响规律,结果表明自由基聚合过程中凝胶效应使共聚物分子质量随转化率升高而显著增大;推导并关联了共聚物平均分子质量模型,在凝胶效应出现之前,该模型计算值与实验值平均偏差８％,为ＭＭＡ－Ｓｔ共聚物的生产控制提供了理论依据。     

丁炔二醇中微量甲醛的分光光度测定研究

用３甲基２苯并噻唑酮腙（ＭＢＴＨ）作显色剂,用分光光度法测定了丁炔二醇中微量甲醛．表观摩尔吸光系数为５．１７×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,最低检测限为４．８μｇ／Ｌ,加标回收率９９％以上,相对标准偏差小于３％．醛含量在０～１．４ｍｇ／Ｌ范围服从比尔定律．方法重复性好,灵敏度高,操作简便,能满足丁炔二醇质量控制分析要求．     

Fabrication of ultralight 3D graphene/Pt aerogel via in situ gamma-ray irradiation and its application for the catalytic degradation of methyl orange

Abstract

In this work, we reported a facile and environmentally friendly approach for the preparing of 3D graphene/Pt aerogel by gamma irradiation at room temperature. Graphene oxide (GO) and platinum ion are simultaneously reduced and self-assembled into a three-dimensional (3D) macro porous structure. Pt NPs with diameter between 2.3 and 5.5?nm were homogeneously attached onto the graphene sheets of the 3D network structure. The catalytic efficiency towards the degradation of methyl orange (MO) of the 3D GA/Pt composite is 108 times higher than that of the pure Pt NPs under the same experimental conditions.     

在聚砜微滤膜表面接枝聚合叔胺单体DMAEMA及接枝膜对水介质中毒性阴离子的吸附与分离特性

采用相转化法制得了氯甲基化聚砜(CMPSF)微孔滤膜,以乙二胺为试剂对CMPSF膜进行化学改性,膜表面的伯胺基与水溶液中的过硫酸铵构成表面引发体系-NH_2/S_2O_8~(2-),使叔胺单体甲基丙烯酸二甲基氨基乙酯(DMAEMA)发生接枝聚合,获得了多孔接枝膜PSF-g-PDMAEMA。考察了接枝聚合的规律,对接枝膜进行了充分表征,考察研究了接枝膜对2种毒性阴离子CrO_4~(2-)及MoO_4~(2-)离子的吸附性能和膜分离去除行为。研究结果表明,控制水溶液中过硫酸铵的质量分数为1%,温度为50℃,可制得PDMAEMA接枝度为0.64 mg/cm~2的接枝膜。在酸性及中性水溶液中,凭借强烈的静电相互作用,多孔接枝膜PSF-g-PDMAEMA对毒性阴离子CrO_4~(2-)离子及MoO_4~(2-)离子均会产生强吸附作用;以该多孔接枝膜为滤膜进行膜分离过程,通过选择性吸附,可有效地去除水介质中的CrO_4~(2-)离子。     

超声波本体聚合在甲基丙烯酸甲酯-Al2O3陶瓷膜注凝成型中的应用研究

通过探讨水浴加热预聚合、微波恒温预聚合、微波预聚合及超声预聚合反应方式对甲基丙烯酸甲酯(MMA)进行预聚合反应,来确定适合作为Al2O3陶瓷膜注凝成型工艺中的预混液制备方式。结果表明:超声的空化作用能够有效地加快预聚合的反应速率,且在预聚合反应过程中,超声波的机械振动作用使MMA反应均匀,且不会发生局部爆聚现象。适合作为MMA预聚合的引发剂为偶氮二异丁腈(AIBN),其最佳用量为0.08%。发现微波的"致热效应"是MMA聚合速率加快的原因。     

醋酸甲酯在离子交换树脂上的水解动力学

本文用间歇搅拌釜式反应器对醋酸甲酯在离子交换树脂上的水解动力学进行了实验测定,得出了消除内外扩散影响的水解反应速率数据,归纳出了通用的动力学方程。其过程满足单点吸附机理,受表面反应控制。     

桐酐与甲基四氢苯酐复合固化环氧体系的性能

研究了不同配比的环氧树脂618/桐酸甲酯酸酐(MeMA)/甲基四氢苯酐(MeTHPA)固化物的固化行为。测定了固化物热变形温度、拉伸强度、弯曲强度、冲击强度及体积电阻等,解析了体系固化前后的红外光谱。结果表明:混合酸酐固化剂中MeTHPA与MeMA的配比为9∶1时,与618环氧树脂固化所得的产物综合性能最佳。2 000 h人工加速老化后其力学性能未见下降。     

Grafting kinetics of poly(methyl methacrylate) on microparticulate silica

Grafting of poly(methyl methacrylate) (PMMA) on microparticulate silica was achieved by initiating the polymerization of MMA by 4,4′-azobis(4-cyanopentanoic acid) that was covalently bound to the silica surface. The initiator seems to be destabilized upon binding it to the silica surface. The kinetics of the graft polymerization are described and are largely affected by the Trommsdorff effect, which makes it possible to graft a high amount of PMMA on silica.     

异丁烯两段法制甲基丙烯酸甲酯

将异丁烯三步法制甲基丙烯酸甲酯简化为两段法,异丁烯首先被氧化到甲基丙烯醛(MAL),再将甲基丙烯醛氧化到甲基丙烯酸和酯化为甲基丙烯酸甲酯(MMA)的反应合并为一步进行,缩短了工艺流程,提高了产率。第一段用共沉淀法制备含有镧系元素La的MoBiFeCoSbLaCsO催化剂,氧化反应在固定床反应器中进行。反应温度365℃,原料气n〔i(C4H8)〕∶n(O2)∶n(N2)=6∶19∶75,空速1800h-1。异丁烯转化率为93 8%;生成MAL的选择性为88 9%。第二段反应的催化剂为Pd5Pb2FeLa,反应温度为70℃,空气流速为100mL min。MAL转化率为89 2%;生成MMA的选择性为92 3%。     

STUDY OF THE PARAMETERS CONTROLLING THE ALTERNATING COPOLYMERIZATION OF METHYL METHACRYLATE AND STYRENE

The copolymerization of methyl methacrylate and styrene, in the presence of zinc chloride, was conducted in the aqueous phase. The zinc chloride acting as a complexing agent

Among the factors affecting the polymerization yield, we have; the level of complexing agents, the monomer ratio and the temperature

The polymers were characterized for their molecular weight (G.P.C.) and analyzed by N.MR, and D.T.A

A model taking into account the various parameters is proposed.