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分别以羟甲基丙烯酰胺(NHA)、苯乙烯(St)为接枝单体,过氧化二异丙苯(DCP)为引发剂,用双螺杆挤出机制备了聚丙烯(PP)的接枝共聚物PP-g-NHA和PP-g-NHA/St。红外分析表明,NHA和St接枝到PP链上形成接枝共聚物。探讨了NHA用量、St用量、DCP用量及加工温度、螺杆转速对接枝率及接触角的影响。结果表明,NHA的最佳用量是3 %,此时接枝率达到最大值为1.6 %,接触角最小为83 °;随着DCP用量的增加,接枝率先增大后下降;加工温度不能太高,螺杆转速一定要大于40 r/min。 相似文献
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本文采用熔融接枝方法制备了聚丙烯接枝丙烯酰胺甲基丙烷磺酸共聚物,用光电子能谱,热分析仪器及红外光谱法对接枝物进行了定性定量表征,研究了单体,引发剂,螺杆转速及反应温度对接枝率和接枝效率的影响。 相似文献
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N-羟甲基丙烯酰胺对硅丙乳液及乳胶膜性能的影响 总被引:2,自引:0,他引:2
将N-羟甲基丙烯酰胺(NMA)、端乙烯基聚硅氧烷大单体与丙烯酸酯类单体进行乳液共聚合反应,制备了稳定的自交联型的硅丙乳液。通过聚合过程的动力学,聚合稳定性,乳胶粒的粒径大小和分布,以及乳胶膜的耐水性和力学性能测试,结合乳胶粒的微观形态和胶膜的红外光谱和DSC分析,讨论了NMA的引入及聚合方法对硅丙乳液和乳胶膜性能的影响。结果表明,在NMA适量加入的情况下,聚合反应速度加快,聚合稳定性提高,乳胶膜的耐水性增强,并使乳胶膜的力学性能也得到较大的提高。 相似文献
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聚丙烯固相接枝N—羟甲基丙烯酰胺(HMA):2.PP—g—N—HMA/PVC合金的研究 总被引:2,自引:0,他引:2
本文采用固相接枝方法制备聚丙烯接枝N-羟甲基丙烯酰胺共聚物,并与PVC进行共混,详细考察了合金的力学性能,加热稳定性及微观形态结构的变化。 相似文献
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采用甲基丙烯酸甲酯、丙烯酸丁酯和丙烯酸为反应单体,以N-羟甲基丙烯酰胺(NMA)为功能单体,通过预乳化半连续种子乳液聚合工艺制备了NMA改性核壳型丙烯酸酯乳液,讨论了NMA用量对乳液的凝胶率及离心稳定性和贮存稳定性的影响,并对乳胶膜的吸水性、力学性能及耐热性进行了表征。结果表明:当NMA的用量为1.5%(wt)时,乳液的凝胶率仅为0.23%(wt),具有良好的离心稳定性和贮存稳定性,乳胶膜的吸水性由6.0%(wt)下降至4.5%(wt),铅笔硬度和冲击强度分别由1 H和52 cm提高至2 H和55 cm以上,弯曲强度、附着力及耐热性俱佳。 相似文献
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N-羟甲基丙烯酰胺含量的测定 总被引:5,自引:0,他引:5
<正> 由丙烯酰胺与甲醛合成的N-羟甲基丙烯酰胺(CH_?CHCONHCH_2OH)作为一种理想的交联剂广泛地应用于纺织、塑料、皮革、涂料等工业部门。通常用蒸氮法测定总氮量以确定其含量,由于样品中含有微量的丙烯酰胺,往往使结果偏高。本文采用次碘酸盐氧化-碘量法,获得满意结果。 1.方法原理碘在氢氧化钠溶液中生成次碘酸钠,它既能氧化样品中的游离甲醛,又能氧化N-羟 相似文献
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介绍了 PMR内标绝对测定法测定 N-羟甲基丙烯酰胺的含量的新方法 ,在 δ4和 δ9处有 N-羟甲基丙烯酰胺的 PMR吸收峰 ,而在 δ7附近却没有吸收峰 ,所以可以用苯作为内标物 (其吸收峰在 δ7.3) ,同时丙酮作为溶剂 (它的所有的吸收峰都小于 δ4 ,不能检测出来 ) ,这样就选择 CH2 OH 的吸收峰进行测定。溶剂峰、杂质峰和 N-羟甲基丙烯酰胺以外的其它峰不会干扰内标物苯和 CH2 OH 的吸收峰。作者以作了方法的精确度测定 ,结果满意 ,同时也讨论了该方法的有关问题 相似文献
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采用丙烯酰胺接枝法对聚丙烯(PP)多孔膜表面进行亲水化改性,考察了硝酸浓度、接枝时间以及水解时间对膜结构和性能的影响。随硝酸浓度增加,接枝度先增后降,膜表面的水接触角先减小后增大;随接枝时间延长,接枝度先增加后几乎不变,水接触角先减小后趋于恒定;随水解时间延长,接枝度几乎不变,而水接触角先减小后趋于恒定。优选的亲水化改性条件下,PP多孔膜的接枝度为1 147μg/cm2,水接触角由124°降至47°。过膜压差为0.5MPa时,聚酰亚胺/PP纳滤复合膜的纯水通量和对1 g/L的Na2SO4溶液的截留率分别可达11.89 L/(m2·h)和92.86%。 相似文献
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将丙烯酸丁酯(BA)与N-羟甲基丙烯酰胺(NA)共聚合制备柔性共聚物P(BA-NA),再用P(BA-NA)增韧聚乳酸(PLA),研究了增韧体系的力学性能、微观形态与共聚单体配比、共聚物含量之间的关系。当n(BA)/n(NA)为30∶1,w[P(BA-NA)]为8%时,PLA/P(BA-NA)复合材料的拉伸断裂应变提高了约97倍,悬臂梁缺口冲击强度提高了1.5倍,拉伸强度为39 MPa。采用扫描电子显微镜观察发现,P(BA-NA)能够均匀分散在PLA基体中,两者相容良好。 相似文献
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Heung Jae Chun Sung Min Cho Young Moo Lee Hyun Kyu Lee Tae Suk Suh Kyung Sub Shinn 《应用聚合物科学杂志》1999,72(2):251-256
Liquid phase ultraviolet irradiation in the presence of benzophenone as a photosensitizer and barium hydroxide as a pH controller were used to graft the mixtures of acrylic acid and acrylamide to a polypropylene surface. The surface of the grafted polypropylene samples were characterized by Fourier transform infrared spectroscopy‐attenuated total reflectance, electron spectroscopy for chemical analysis, scanning electron microscopy, and a contact angle meter. The pH value of the reaction medium that produced the graft with equal molar ratio was found to be ∼ 3.77. The optimal reaction condition was found at a monomer feed of 25%, a reaction time of 30 min, and a benzophenone concentration of 1%. Surface tension of the samples increased to a value of 40 dyn cm−1 due to the graft of the hydrophilic monomers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 251–256, 1999 相似文献
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The electrical properties of polypropylene (PP), grafted polypropylene (PP‐g‐PVP), and modified‐grafted PVP with α‐cyano‐β‐(2‐thienyl) crotononitrile were investigated. Also, the electrical characteristic of the modified‐grafted PVP subjected to γ‐irradiation (60 kGy) was studied. The results show that the σ of trunk polymer undergoing different degree of grafting generally increases as function of the grafting yield. The grafting yield between 64.1 and 149% resulted in a progressive decrease in ΔEσ value. Inclusion of sulfur‐containing substrate in different films, having various grafting yields, leads to both increase and decrease in σ values. A significant increase in σ values is observed upon inclusion of sulfur‐containing substrate having maximum grafting yield (149%). These changes are accompanied by fluctuation in σ values. The exposure of sulfur‐containing substrate in grafting film to a dose of 60 kGy results in a significant decrease in ΔEσ values for the films undergoing a grafting yield between 64.1 and 149%. The observed changes in ΔEσ of different films investigated could be attributed mainly to corresponding changes in σ values. The observed improvement in electrical properties is mainly because of possible increase in concentration of charge carrier and/or their mobilities. The scanning electron micrographs of some selected films show significant changes in the morphology of the films investigated due to changing the grafting yield, inclusion of sulfur‐containing substrate, and exposure to γ‐irradiation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3797–3803, 2007 相似文献
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In this article, polyaniline (PANI)/cotton composite were prepared by in situ polymerization on the grafted cotton. First, acrylamide was grafted onto cotton cellulose using a radical graft polymerization process and some influencing factors were studied. Then polyaniline/cotton conductive composite fabrics were prepared by chemical in situ polymerization on the grafted cotton. The influences of the concentration of ammonium persulfate, aniline, hydrochloric acid, and the reaction time to the conductivity and K/S of composite fabric were studied. By contrasting, graft brought on an improvement of about one order of magnitude to the conductivity of composite fabric. The strength, TG, FTIR‐ATR, and SEM of prepared fabric were measured. The thermal stability and tear strength of composite fabric reduced, whereas PANI exhibited a rough but uniform, coherent PANI coating on surface of cotton fiber. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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采用DSC方法测试了小本体聚丙烯(PP)及其接枝丙烯酰胺(PP-g-AM)非等温结晶过程的释热情况,并对两组实验数据分别运用Jeziorny法和Mo法进行了处理和比较.结果表明,两种方法均可准确地描述PP及PP-g-AM的非等温结晶过程.PP接枝前后Avrami指数n无明显改变,表明两者结晶机理基本相同;由Jeziorny法得到接枝产物的校正晶体增长速率常数Zc略大于纯PP的Zc;由Mo法计算得出,PP-g-AM的F(T)值略小于纯PP的F(T),表明接枝物的相对结晶速率略大于纯PP的相对结晶速率. 相似文献
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Sisal fiber (SF) surface modification was carried out by grafting with methyl methacrylate (MMA) using cerium and ammonium nitrate as initiator. The effects of reaction time, monomer, and initiator concentration on the grafting parameters were systematically investigated. The results showed that MMA was successfully grafted onto the sisal fiber surface. The PMMA‐grafted sisal fibers were melt blended with polypropylene (PP) and then injection molded. The PP/SF composites were characterized by means of thermal analysis, mechanical testing, wide‐angle X‐ray diffraction, and SEM examination. PMMA grafted onto the surface of SF enhanced the intermolecular interaction between the reinforcing SF and PP matrix, improved the dispersion of SF in the PP matrix, and promoted the formation of β‐crystalline PP. These enhanced the thermal stability and mechanical properties of PP/SF composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1055–1064, 2003 相似文献
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