硅溶胶/聚丙烯酸酯复合乳液的结构和性能研究

采用普通乳液聚合的方法,制备了硅溶胶/聚丙烯酸酯复合乳液.通过透射电镜(TEM)、傅里叶红外光谱仪(FT-IR)和动态激光散射仪(DLS)等对复合乳液中乳胶粒子的结构进行表征,并对复合乳液的涂膜性能进行研究.结果表明,所制备的复合乳液粒子具有核-壳结构,其中核是纳米级的SiO2粒子,壳是聚丙烯酸酯.性能测试结果表明,核-壳结构的存在使得复合乳液的涂膜在硬度、附着力和化学稳定性等方面均优于纯丙乳液及硅溶胶/聚丙烯酸酯的共混乳液.     

细乳液聚合制备改性硅溶胶／聚丙烯酸酯复合乳液

常温下一步法制备改性硅溶胶,并通过细乳液聚合制备改性硅溶胶／聚丙烯酸酯复合乳液。考查了温度对聚合速率和单体转化率的影响以及不同乳化剂含量下聚合过程中乳胶粒粒径的变化情况;测试了乳胶膜的吸水率,并用接触角法表征了乳胶膜的表面自由能。     

聚氨酯/聚丙烯酸酯复合乳液的研制进展

综述了近年来聚氨酯－丙烯酸酯（PUA）复合乳液研究的新进展，总结介绍了各类聚氨酯－聚丙烯酸酯复合乳液（PUA共混复合乳液、PUA复合核／壳乳液、互穿网络PUA复合乳液）的制备方法和性能特点。并对该领域进一步的发展作了展望。     

核壳型水性聚氨酯-聚丙烯酸酯复合乳液的制备及其影响因素

用丙烯酸酯改性水性聚氨酯(PU)制备了具有核壳结构的PU-聚丙烯酸酯(PA)复合乳液,对其结构进行了表征,研究了亲水性扩链荆二羟甲基丙酸(DMPA)用量、NCO/OH(摩尔比)、乳化剂用量、核壳质量比对乳液和涂膜性能的影响.结果表明,所制备的乳液为核壳型PU-PA复合乳液;当DMPA的质量分数为5.5%-6.0%、NCO-OH总摩尔比为1.3-1.4、NCO/OH初始摩尔比为4.5-5.5、乳化荆质量分数为1.0%、核壳质量比为30/70时,可得到性能较佳的PU-PA复合乳液和涂膜.     

改性硅溶胶 /聚丙烯酸酯复合乳液的制备及性能研究

为了提高无机纳米粒子在有机聚合物中的相容性,以及无机 -有机复合材料的贮存稳定性,用硅溶胶和双丙酮丙烯酰胺（ DAAM）制备出改性硅溶胶,然后以改性硅溶胶为核,以甲基丙烯酸甲酯（ MMA）、α-甲基丙烯酸（ MAA）和丙烯酸丁酯（ BA）为原料,通过半间歇乳液聚合法制备出了核壳结构的改性硅溶胶 /聚丙烯酸酯复合乳液（ DAAM-SiO2/WPA）,并研究了硅溶胶对聚丙烯酸酯复合乳液和涂膜性能的增强作用。结果表明：用质量分数 3%的双丙酮丙烯酰胺（ DAAM）改性硅溶胶,制备的复合乳液的综合性能增强,水接触角为 77. 17°,吸水率为 11. 27%,拉伸强度为 7. 22 MPa,断裂伸长率为 431. 49%。TEM测试表明复合乳液具有核壳结构。相比较纯丙烯酸酯（ WPA）涂膜,复合乳液涂膜的耐水性、热稳定性和力学性能都有显著提高。并且与聚丙烯酸酯乳液和硅溶胶的直接物理混合溶液（ SiO2/WPA）相比,改性硅溶胶 /聚丙烯酸酯复合乳液的室温贮存稳定性超过 12个月,无机相和有机相的相容性好。     

聚丙烯酸酯/纳米二氧化硅复合乳液的制备

将甲基丙烯酸羟乙酯与硅酸四乙酯经酯交换制得的二甲基丙烯酰氧基硅酸二乙酯与丙烯酸酯进行乳液聚合，制得了不同二氧化硅含量的稳定聚丙烯酸酯/纳米二氧化硅复合乳液；讨论他乳化剂种类和用量，以及不饱和硅酸酯单体用量对聚合转化率及乳液稳定性的影响。用红外光谱和透射电镜表征了乳胶膜。试验结果表明，采用乳液聚合可以制得原位水解并稳定分散的聚丙烯酸酯/纳米二氧化硅复合乳液。     

聚丙烯酸酯/苯乙烯复合乳液制备及性能的研究

本文以丙烯酸甲酯和丙烯酸丁酯为核单体,以丙烯酸丁酯和苯乙烯为壳单体,采用种子聚合技术,讨论了各种影响因素对复合乳液制备及乳液涂膜性能的影响,合成了水稀释稳定性,电解质稳定性和机械稳定性都很好和近似为中性而无需重新调整ｐＨ值的高分子复合乳液。     

聚氨酯-聚丙烯酸酯复合乳液的合成与表征

将自制的自乳化 PU乳液代替常规乳液聚合的乳化剂 ,用丙烯酸丁酯为单体 ,偶氮二异丁腈为引发剂在 PU乳液中均聚形成 PUA乳液 ,对该体系的聚合动力学及复合乳液的胶膜性质进行了研究。     

种子乳液聚合法制备有机硅改性聚丙烯酸酯乳液

采用核壳乳液聚合技术,以端乙烯基硅油与丙烯酸酯类单体共聚,合成了有机硅改性聚丙烯酸酯乳液.考察了乳化剂类型、比例、用量以及甲基丙烯酸、甲基丙烯酸缩水甘油酯、乙烯基硅油的用量对乳液聚合稳定性及乳液性能的影响.结果表明,十二烷基苯磺酸钠(SDBS)和辛基酚聚氧乙烯(10)醚(OP-10)复配可产生协同效应,且m(SDBS):m(OP-10)=2、质量分数为3%～4%(相对于单体总质量)时,乳液的稳定性好;甲基丙烯酸缩水甘油酯的质量分数小于4%、端乙烯基硅油的质量分数小于8%时,乳液的聚合稳定性较好;随着甲基丙烯酸用量的增加,乳液的聚合稳定性增加,乳胶粒粒径变小.     

微波辐射制备室温自交联含氟聚丙烯酸酯乳液

在微波辐射下,以甲基丙烯酸十二氟庚酯(DAAM)为含氟单体,双丙酮丙烯酰胺为功能单体,己二酸二酰肼为交联剂,阴离子十二烷基硫酸钠和非离子脂肪醇聚氧乙烯醚为复合乳化剂,在过硫酸钾的引发下,制备了可室温自交联的含氟聚丙烯酸酯乳液。考察了交联单体用量对转化率、粒径分布及分布指数和乳胶膜吸水率的影响。w(DAAM)为5%时,乳液乳胶粒呈球形,平均粒径在60~70 nm。随着DAAM用量的增加,乳胶膜吸水率减小,此时交联起主导作用;进一步增加DAAM用量,乳胶膜吸水率反而增大,此时亲水性起主导作用。     

硅溶胶／聚丙烯酸酯乳液型压敏胶的制备与性能

采用半连续加料乳液聚合方法制备了硅溶胶／聚丙烯酸酯核／壳结构聚合物,采用动态光散射方法跟踪了复合乳胶粒的粒径随反应进程的变化,其理论粒径与实测值基本一致,说明该聚合过程没有明显的二次成核过程。考查了壳层硬单体-甲基丙烯酸甲酯（MMA）含量对乳液聚合的影响,通过动态热机械分析仪（DMA）对聚合物的黏弹性能进行了表征,对制成的胶粘剂进行了压敏特性的测定,并与复合粒子的分子结构进行了关联。研究表明,随着MMA含量的增加,压敏胶的初粘性略有下降,而持粘性显著提高,剥离强度呈先升后降的趋势。     

甲基改性硅溶胶的制备与疏水性分析

通过溶胶-凝胶工艺,以甲基三甲氧基硅烷(MTMS)为基料对碱性硅溶胶进行改性,将改性后的硅溶胶涂覆在铝板表面,制备出具有低表面能、耐高温的含硅透明疏水涂层.考察了pH和热处理温度对涂层水接触角的影响,以傅里叶变换红外光谱仪对涂层进行了表征,用同步热分析仪对比研究硅溶胶和改性硅溶胶干燥后在空气中的热重-差热(TG-DTA...     

Synthesis and characterization of polyimide/silica hybrid nanocomposites

Polyimide/silica (PI/SiO₂) hybrid nanocomposites were prepared by the sol‐gel process directly from a soluble polyimide. This soluble PI was synthesized from a diamine with a pendant phenyl hydroxyl group, 4,4′‐diamino‐4″‐hydroxy triphenyl methane (DHTM) and a dianhydride, pyromellitic dianhydride (PMDA), followed by cyclodehydration. Three ways of preparing PI/SiO₂ hybrid nanocomposites were investigated in this study. Two of them used the coupling agent 3‐glycidyloxy propyl trimethoxysilane (GPTMOS) to enhance the compatibility between PI and silica. The coupling agent can react with the PI to form covalent bonds. The structures of the modified hybrid nanocomposites were identified with a FTIR, whereas the size of the silica in polyimides was characterized with a scanning electron microscope. The size of silica particles in the modified system was <100 nm. The covalently bonded PI/SiO₂ hybrid nanocomposites prepared by the novel third approach exhibited good transparency when the silica content was <15%. Moreover, their thermal and mechanical properties exhibited a significant improvement. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 382–393, 2004     

硅溶胶建筑防水堵漏剂的研制

研究了一种以硅溶胶为主体的建筑防水堵漏剂 ,考查了各主要原料用量对产品性能的影响。并对产品的稳定性能、渗透性能与防水性能进行测试。结果表明 ,本剂渗透力强 ,防水阻漏效果好。     

含3nm硅溶胶的苯丙杂化乳液的制备与性能研究

在单一乳化剂存在下 ,用原位分散聚合方法制备了含 3 nm硅溶胶的苯丙杂化乳液。通过 FTIR、粒径分析、ζ电位和流变性能测试 ,表征了杂化乳液中的杂化效应、微粒形态及乳液稳定性 ,并与分别由 3 nm和 1 0 nm硅溶胶与苯丙乳液直接共混形成的杂化乳液进行了比较。与直接共混的杂化乳液成膜后的力学性能相比 ,由原位分散聚合形成的 3 nm硅溶胶杂化乳液成膜后 ,显示出较高的拉伸强度、拉伸模量和断裂伸长率。     

Durable nanocomposite adhesives based on polyacrylates and surface-modified colloidal silica

Surface-modified colloidal silica (M-CS) nanoparticles were successfully synthesized from colloidal silica (CS) and methyltrimethoxysilane using sol–gel method and characterized by Fourier transform-infrared spectroscopy. Both CS and M-CS were then incorporated into acrylic adhesives. M-CS particles in 2-ethoxyethanol had similar particle size to pure CS based on the characterization by DLS. The morphologies of M-CS particles in acrylic adhesives examined by TEM showed more homogeneous dispersities than that of pure CS which were aggregated and phase separated in acrylic adhesives. In addition, the thermal properties of the nanocomposite acrylic adhesives determined by thermogravimetric analyses and differential scanning calorimetry showed higher glass transition temperature and thermal properties than pure acrylic adhesives. Finally, the 180° peel strength of nanocomposite acrylic adhesives was higher than pure adhesives with improved durabilities.     

Synthesis of core‐shell fluoroacrylate copolymer latex via emulsion polymerization and its application in ink‐jet ink

Core‐shell fluoroacrylate copolymer latex was synthesized via semicontinuous seed emulsion polymerization, in which ethyl acrylate was utilized to prepare core, and methyl methacrylate, butyl acrylate, methacrylate acid, and hexafluorobutyl methacrylate were employed to constitute the shell. So the yielded latex particles had the soft core and hard shell. Multifunction and low viscosity of the latex had been applied as the binder of latex inks. The ζ potential showed that the latex particles had high thermodynamic stability. The latex and latex inks exhibited viscosity plateau of Newtonian fluid behaviors. Rheological tests revealed that viscous behaviors dominated in the latex and latex inks. However, there was some interaction among the latex and pigment particles. The hydrophobicity of the cast films of the latex increased with the amount of the fluoroacrylate monomer. Fluorine tended to migrate to the interface between the cast film and air. Therefore, the hydrophobicity was derived from the fluorine enrichment phenomena on the top side of the cast films. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

锆质溶胶的制备与性能表征

采用工业ZrOCl2.8H2O,结合非均匀沉淀法及水热法制备了锆溶胶。系统分析了不同浓度的前躯体溶液、pH值以及缓冲溶液等因素对制备的锆溶胶粒径、稳定性的影响。通过非均匀沉淀法,在室温条件下,缓慢将氨水与氧氯化锆溶液滴加至缓冲溶液中,制得前驱体沉淀,经抽滤洗涤后用硝酸重新分散滤饼,于75℃水浴加热5~12 h,制得澄清透明状纳米级锆质溶胶。结果表明,溶胶中粒子呈伞状、柱状,且分散均匀。溶胶粒子大小为12~15 nm。在pH值为0.8~1.4条件下,溶胶能长期稳定存在。干燥后的锆质凝胶以非晶态形式存在,且非晶态凝胶在450℃左右转变为四方相ZrO2。经1100℃热处理,保温1 h转变为单斜相ZrO2。     

以硅灰、白炭黑、硅溶胶为硅源合成碳化硅晶须的研究

以硅灰、白炭黑、硅溶胶为硅源,炭黑为碳源,采用碳热还原法合成碳化硅晶须,通过XRD及SEM对合成产物的物相及形貌进行分析,探讨了合成温度(分别为1 400、1 450、1 500、1 550℃)、硅源、n(C)∶n(SiO2)对合成碳化硅晶须的影响.结果表明:n(C)∶n(SiO2)为2.4～3.6,合成温度为1 500 ℃,保温3 h时,硅溶胶与炭黑反应没有生成碳化硅晶须,硅灰、白炭黑与炭黑反应均生成碳化硅晶须;以硅灰为硅源合成碳化硅晶须的质量及数量明显优于以白发黑为硅源合成碳化硅晶须;合成碳化硅晶须的最佳n(C)∶n(SiO2)为3.3.