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Model reactive latices were synthesized by semicontinuous emulsion copolymerization of n‐butyl methacrylate and acetoacetoxyethyl methacrylate or dimethylaminoethyl methacrylate. The two functional latices were then blended in various ratios to study the influence of blend composition on crosslinking and mechanical properties of the resulting films. Crosslinking was quantified through swelling measurements. It was found that the crosslink density increased with increasing amounts of acetoacetoxy‐functional polymer. In addition, the crosslink density exhibited two maxima, at 30/70 and 70/30 (acetoacetoxy‐functional latex/amino‐functional latex) blend compositions. The mechanical properties of the films were quantified by dynamic mechanical analysis (DMA). It was shown that optimal mechanical properties occurred when the particles packed most efficiently at the 30/70 and 70/30 blend compositions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3774–3779, 2007 相似文献
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采用阳离子乳化剂聚二烯丙基二甲基氯化铵(PDDA)对氨基硅溶胶进行改性制备改性氨基硅溶胶(MSS),然后将其与天然乳胶(NRL)进行杂凝聚制得MSS/NRL膜材料,分析了MSS,MSS/NRL膜材料的结构、粒径、Zeta电位及形态,考察了MSS/NRL膜材料的力学性能及耐紫外老化性能。结果表明,MSS与NRL共混后粒径较NRL增大;氨基硅溶胶经PDDA改性后呈弱正电性,能在杂凝聚共混环境下与带负电荷的乳胶粒子形成多层次核-壳结构;随着MSS添加量的增加,MSS/NRL膜材料的拉伸强度呈先增后减的趋势,当MSS质量分数为0.35%时,膜材料的拉伸强度达到21.98 MPa的最大值,扯断伸长率达到750%;MSS/NRL薄膜的耐紫外老化性能在老化12 h以后较NRL薄膜提高10%以上。 相似文献
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以双丙酮丙烯酰胺(DAAM)为官能性单体合成了带酮羰基的聚丙烯酸酯核壳乳液,将其与己二酸二酰肼(ADH)在室温下交联制备了聚丙烯酸酯多孔乳胶膜,考察了乳液壳层组成、ADH用量、致孔剂用量及种类对乳胶膜渗透性能的影响。研究结果表明,当壳层组成BA/(MMA+AA+DAAM)质量比为2.5/2.5时,乳胶粒子没有完全变形,粒子间相互融接堆积,结合致孔剂的作用,形成了内部呈疏松多孔结构的乳胶膜,膜的渗透量较高;研究进一步揭示,限制大分子链段的热运动有利于维持乳胶膜的多孔结构,从而获得较高的渗透量;此外,发现以葡萄糖、聚乙二醇300(PEG300)为致孔剂时可使乳胶膜获得较高的渗透量。 相似文献
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The effects of latex coalescence and interfacial crosslinking on the mechanical properties of latex films 总被引:1,自引:0,他引:1
The effects of latex coalescence and interfacial crosslinking on the mechanical properties of latex films were extensively investigated by means of several series of model latexes with varying backbone polymer crosslinking density and interfacial crosslinking functional groups. It was found that the tensile strength of crosslinked model latex films increased with increasing gel content (i.e. crosslinking density) of latex backbone polymers up to about 75% and then decreased with further increase in gel, while their elongation at break steadily decreased with increasing gel content. These findings showed that latex particle coalescence was retarded above a gel content of about 75% so that the limited coalescence of latex particles containing gel contents higher than 75% prevented the tensile strength of crosslinked latex films from increasing by further crosslinking the latex backbone polymers. This was contrary to the theory of rubber elasticity that the tensile strength increases with increasing molecular weight and crosslinking density. This limitation was found to be overcome by the interfacial crosslinking among latex particles during film formation and curing. This paper will discuss the effects of both latex backbone polymer and interfacial crosslinking on latex film properties. It will also discuss the development of self-curable latex blends and structured latexes containing co-reactive groups: oxazoline and carboxylic groups. 相似文献
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This review is focused on the features, preparation and applications of uniform cationic polymer latex particles, as well as on the formation mechanism of uniform latex particles. Substantial progress in the size and shape control of polymer latex particles has been made using several methods such as dispersion polymerization, conventional emulsion polymerization, surfactant‐free emulsion polymerization and seeded emulsion polymerization. Uniform cationic polymer latex particles have wide applications such as drug carriers, diagnostics, templates and additives. However, two major problems are the inhomogeneous size and low surface charge density, which limit further functionalization and the application of cationic polymer latex particles. Finally, the future trends and perspectives are described. Copyright © 2012 Society of Chemical Industry 相似文献
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聚丙烯酸酯—聚有机硅氧烷复合乳液的合成与性能 总被引:11,自引:0,他引:11
以在丙烯酸甲酯、丙烯酸丁酯、甲基丙烯酸、八甲基环四硅氧烷(D4)和乙基七甲基环四硅氧烷(VD4)为共聚单体,在85℃下采用一次投料合成了稳定的聚丙烯酸酯-聚有机硅氧迷雾复合乳液。实验结果表明,当VD4/D4摩尔比为0.008,有机硅质量分类小于20%时,单体转化率均高于82%,胶乳粒径为50-60nm,且粒径分布均匀;当有机硅质量分数大于25%时,聚合过程中有凝聚物产生,乳液不稳定,胶膜的拉伸强度 相似文献
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采用两步法工艺路线,以PA6齐聚物、聚醚和少量交联剂为原料共聚合成聚醚酰胺热塑性弹性体(TPAE)。对TPAE进行模拟纺丝,对初生纤维进行拉伸和热定型。测定了纤维的力学性能。利用WAXD分析了交联剂对TPAE结晶性能的影响,讨论了纤维弹性及回复率与纺丝条件、交联剂用量的关系。结果表明,随交联剂含量的增加,拉伸丝较初生丝的结晶度提高幅度小,交联剂的化学交联作用明显。交联剂的引入使TPAE纤维断裂强度和弹性回复率提高,断裂伸长率降低,交联剂质量分数(相对PA6)为0.7%时,TPAE纤维的弹性回复率可提高到95%以上。 相似文献
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The surface composition of films obtained from acrylic latexes (45 wt% MMA, 55 wt% BuA) stabilized by two anionic surfactants (either sodium dodecyl sulphate (SDS) or sodium dodecyl diphenyl ether disulphonate (SDED) has been studied by attenuated total reflection with Fourier transformed infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The results of this surface analysis are summarized and used to interpret adhesion properties of the films on glass substrate. Adhesion properties were derived from peeling tests. In the case of SDED, the peel strength increases with surfactant surface concentration. This is due to strong polar interactions between the hydrophilic part of the surfactant and the polar groups of the glass surface and to the anchorage of the hydrophobic part of the surfactant in the copolymer matrix. In the case of SDS, the peel strength decreases with increasing surfactant surface concentration. The same polar interactions as with SDED exist, but the SDS layer at the interface is very thick. It forms what is called a ‘weak boundary layer’ in which rupture propagates easily. 相似文献
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研究了阳离子含氟聚氨酯-丙烯酸酯复合乳液(PUA)中性施胶剂的制备和应用,重点分析了亲水单体、聚丙烯酸酯、含氟丙烯酸酯对阳离子含氟PUA中性施胶剂应用效果和产品稳定性的影响,并用红外光谱(FTIR)和核磁共振氟谱(19F- NMR)对其结构进行了表征.结果表明,当用量为0.8%时,纸张的施胶度大于36.70s;乳液的ξ... 相似文献
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BACKGROUND: Although several cereal proteins have been used to develop fibers and films, it has not been possible to obtain protein materials with good mechanical properties and water stability, even after crosslinking. Previously, high concentrations of glutaraldehyde were used to improve the mechanical properties of protein fibers but the effect of crosslinking conditions on the properties of the crosslinked materials has not been studied in detail. RESULTS: Low concentrations of glutaraldehyde can be used to improve the mechanical properties and water stability of gliadin fibers. Quantitative relationships that can predict the breaking tenacity of the fibers at various crosslinking conditions are developed. Glutaraldehyde crosslinking is more resistant to hydrolysis in neutral pH than under acidic conditions in terms of increasing and retaining the breaking tenacity. The crosslinked fibers show improved resistance to hydrolysis over poly(lactic acid) fibers in aqueous dispersions at pH = 4 and 7 at 50 and 90 °C, respectively. CONCLUSIONS: This study shows that low concentrations of glutaraldehyde can impart excellent mechanical properties to gliadin fibers. The quantitative relationships developed can be used to select the crosslinking conditions such low glutaraldehyde concentration and high temperature or vice versa to obtain the desired improvement in mechanical properties or water stability. Copyright © 2008 Society of Chemical Industry 相似文献
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分别从形貌、结构、力学性能、生物性能等方面综述了交联剂京尼平与戊二醛对再生丝素蛋白的影响。表明京尼平由于毒性低和生物相容性好的特点,发现它比戊二醛更适合运用于蛋白类的物质组织工程。 相似文献
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一种季铵盐阳离子表面活性剂的合成与性质 总被引:1,自引:0,他引:1
以氯丙烯与N,N-二甲基十二烷基胺(DTA)为原料合成了季铵盐阳离子表面活性剂十二烷基二甲基烯丙基氯化铵(DADAC);研究了原料配比、反应温度、反应时间和溶剂等因素对生成物DADAC收率的影响,通过红外光谱、元素分析确定其化学结构。较佳反应条件为:n(氯丙烯)∶n(DTA)=3∶1,无水乙醇为溶剂,50℃下反应24 h,DADAC收率为93.76%。最后测定了产物的表面性能,得到25℃下,DADAC的cmc为5.76 mmol/L,在cmc时的γ=34.2 mN/m,Krafft点<0℃。 相似文献
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采用丙烯酸(AA)、丙烯酸丁酯(BA)混合单体通过乳液聚合方法合成附聚剂,用于聚丁二烯胶乳(PBL)的附聚.研究了附聚时间、附聚剂组成、附聚剂加入量、附聚剂的粒子尺寸等因素对聚丁二烯(PB)胶乳粒径大小的影响.结果表明:附聚时间为40~60 min时,附聚过程基本完成;当BA/AA质量比为80/20时,附聚效果最好;附聚剂在PBL中加入量占PBL总质量的8.3%时,附聚效果明显;PBL平均粒径由原来的96nm附聚到了240~260 nm,粒径得到了明显的增长,合成的附聚剂有良好的附聚效果. 相似文献
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以纸浆纤维素为原料,以功能化离子液体氯化1-(3-氯-2-羟丙基)3-甲基咪唑为阳离子化剂和溶剂,合成了咪唑阳离子纤维素;探讨了反应条件对咪唑阳离子纤维素的取代度的影响,并对其结构与性能进行了表征.结果表明:纸浆纤维素中NaOH质量分数为20%,反应温度为80℃,反应时间为3h时,咪唑阳离子纤维素的取代度达0.85;红... 相似文献
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非对称双子季铵盐阳离子表面活性剂的合成及性能 总被引:17,自引:0,他引:17
以十二烷基二甲基叔胺、盐酸、环氧氯丙烷为原料,合成了中间体N-(3-氯-2-羟丙基)-N,N-二甲基十二烷基氯化铵,后与3种不同烷基链长的长链烷基叔胺反应,得到3种非对称Gemini季铵盐阳离子表面活性剂(Ⅰ~Ⅲ)。通过IR光谱,1HNMR确证了中间体及目的产物的结构。测定了产物的临界胶束浓度cmc及γcmc。cmc分别为1 07×10-3mol·dm-3、1 99×10-3mol·dm-3和9 55×10-3mol·dm-3,γcmc分别为40 9mN·m-1、48 0mN·m-1和50 9mN·m-1。结果表明:所合成的非对称Gemini季铵盐阳离子表面活性剂具有较高的表面活性。 相似文献