室温下原位聚合制备PMMA/PS复合光散射材料

本文通过加入α-羟基乙基二茂铁在室温下采用原位聚合法制备了PMMA/PS复合光散射材料.对样品的光学性能、分子量、和微观结构的分析表明:这种有色复合材料透光率低,但散射能力强;相对于未加添加物的复合材料数均分子量较低,相对分子质量分布加宽;由于自组装材料内部散射体与基体相分离形成个畴,并且随着ST预聚物用量增多,材料内部相分离得到改善.     

添加SBR原位聚合制备PS/PMMA高聚物复合光散射材料

将丁苯橡胶添加到预聚MMA和St的混合溶液中经过原位聚合的方法制备PS/PMMA高聚物复合材料.研究了散射体物质添加量对样品的光学性能的影响.实验结果表明:SBR和预聚MMA对样品的光散射性能产生了协同作用;PS/PMMA高聚物复合材料的雾度值随SBR添加量的改变而产生明显的振荡,而样品的透光率随SBR添加量的改变则其振荡关系存在,但是不显著;PS/PMMMSBR样品的雾度值及透光率随预聚MMA添加量的改变呈现弱的振荡变化关系.形貌分析表明:散射剂能够很好地分散于基体中.     

PS对PMMA光散射性能的影响

室温下将苯乙烯（St）用一定量的引发剂 BPO 引发预聚合,将预聚合的微量 PS 加入到聚甲基丙烯酸甲酯（PMMA）中,从 Mie 散射理论和实验两方面研究了微量 PS 的加入对 PMMA 散射性能的影响。结果表明:用 matlab理论模拟的结果与实验的结果相吻合,随着 St 预聚物的微量增加,散射体粒子的粒径增大,PMMA 的散射性能呈抛物线形式变化,当添加的 St 预聚物的质量分数大约为0.45%时,材料的有效光散射性能最强,接近75%。     

二茂铁和α-羟基乙基二茂铁对MMA本体聚合的影响

聚甲基丙烯酸甲酯(PMMA)一般由本体聚合或悬浮聚合制得.本体聚合具有生产工艺简单,投资少等优点,但本体聚合周期长,反应热排除困难而易产生自动加速效应导致爆聚,因此制约了本体法制备PMMA.研究微量二茂铁及其衍生物α-羟基乙基二茂铁对MMA本体聚合的影响,结果表明:微量二茂铁或α-羟基乙基二茂铁的加入,聚合时间与聚合温度显著降低,在室温下能实现快速聚合;80℃时,当二茂铁的添加量超过0.17%时,MMA无法爆聚,解决了本体法制备MMA的瓶颈,对工业化生产具有一定的指导意义.     

原位预聚法制备PMMA/PS复合光散射材料

将苯乙烯预聚物加入到甲基丙烯酸甲酯单体中进行原位聚合,制备透明、高散射、导光聚合物材料.对预聚反应体系的引发剂用量、预聚时间以及苯乙烯预聚物用量和反应温度等条件对样品的透明性、散射性影响进行了研究.结果表明,在预聚温度80℃时,St预聚物的用量在0.2%～1%,预聚20min能够得到透明高散射导光的高聚物材料.实验表明,随着苯乙烯预聚物用量的增加或预聚时间的延长,材料的透光率下降,散射增强,雾度升高.材料的透光率能够大于85%,雾度大于80%.     

苯乙烯聚合物以及二茂铁衍生物对有机玻璃破碎压力的影响

以甲基丙烯酸甲酯(MMA),在丙酮溶液中聚合的苯乙烯聚合物以及α-羟基乙基二茂铁为原料,BPO为引发剂,将苯乙烯预聚合物以及苯乙烯预聚合物和α-羟基乙基二茂铁分别添加到MMA中进行聚合,并对得到两种材料的破碎压力进行了测试和研究.苯乙烯预聚合物的加入使PMMA的破碎压力提高;加入α-羟基乙基二茂铁后反应容易进行,但是PMMA的破碎压力降低,材料韧性增加.     

不同PMMA对ABS/PMMA合金性能的影响

试验采用两种不同的聚甲基丙烯酸甲酯 (PMMA)与ABS进行共混。并对ABS/PMMA共混物的各项性能进行了较详细的研究。试验结果表明 ,不同分子量的PMMA对ABS/PMMA混合物的光学性能、力学性能以及流变行为都有显著不同的影响     

PMMA/MCM-41复合粒子对环氧树脂复合材料性能的影响

采用气相法先将聚甲基丙烯酸甲酯(PMMA)引入纳米介孔分子筛MCM-41的一维孔道内,制备出PM-MA/MCM-41复合粒子,再与环氧树脂(EP)共混,研究了PMMA/MCM-41复合粒子对EP/(PMMA/MCM-41)复合材料拉伸性能的影响。结果表明,PMMA分子链引入到MCM-41的孔道内,并且孔口处的PMMA与EP产生了较强的界面相互作用,增加了两者的相容性。PMMA/MCM-41复合粒子使EP的拉伸强度、拉伸弹性模量、断裂伸长率均有所提高。     

硅橡胶微球/PS光散射材料的制备与表征

以悬浮聚合法制备了硅橡胶微球的悬浮液,采用喷雾干燥技术制备得到硅橡胶微球。分析了硅橡胶微球的热力学性能、光学性能及比表面积的大小。将硅橡胶微球作为光散射剂添加到聚苯乙烯(PS)树脂中,制得光散射基材。考察了微米级的硅橡胶微球对PS的光学性能及力学性能的影响。结果表明:硅橡胶微球能够在PS树脂中良好分散,能够大幅度提高PS的雾度,当光散射基体中硅橡胶微球质量分数为0.2%时,PS样片(厚度0.9 mm)雾度为88%,透光率为78%。     

基于细乳液聚合法TiO2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯（TiO2/PMMA）纳米复合粒子,考察了引发剂、助乳化剂、乳化剂、单体结构和种类对TiO2/PMMA纳米复合粒子性能的影响。结果表明与十二醇和十六醇相比,十六烷（HD）更能抑制甲基丙烯酸甲酯（MMA）液滴的Ostwald熟化效应,当MMA占TiO2质量分数的60%,HD对单体质量分数的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵（DNS-86）占整个体系的质量分数为2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

Nanocellular Foams of PS/PMMA Polymer Blends

A nanocellular PS/PMMA polymer blend foam was prepared, where bubble nucleation was localized in the PMMA domains. The blend, which contains dispersed nanoscale PMMA islands, was prepared by polymerizing MMA monomers in a PS matrix to form highly dispersed PMMA domains in the PS matrix by diffusion mixing. The resulting blend was foamed with CO₂ at room temperature. A higher depressurization rate at lower foaming temperature made the bubble diameter smaller and the bubble density larger, and a higher PS composition in the blend resulted in a larger bubble density. A void with 40–50 nm in average diameter and a pore density of 8.5 × 10¹⁴ cm^?3 was obtained as for the finest nanocellular foams.

     

PS/PMMA共混物中超声波传播特性研究

利用自行设计的装置,采用改变入射角的方法将超声波纵波和横波导入不相容的聚苯乙烯/聚甲基丙烯酸甲酯(PS/PMMA)共混物体系中。研究了两种波的声速和声衰减随共混体系共混比变化的情况,并结合扫描电子显微镜(SEM)检测得到的相畴尺寸进行了分析。结果表明:共混物中的相畴尺寸与其散射衰减之间存在对应关系;由于横波波长更为接近共混体系中的相畴尺寸,横波的散射衰减明显大于纵波。     

POE/EVA复合发泡材料性能

采用化学发泡法制备以聚乙烯-醋酸乙烯酯(EVA)为基体,不同含量乙烯-辛烯共聚物(POE)及马来酸酐(MAH)接枝的乙烯-辛烯共聚物的复合发泡材料,并研究POE对EVA发泡材料发泡行为及力学性能的影响。结果表明:随着POE含量的增加,一方面增加了发泡材料的弹性,压缩永久变形降低,但拉伸及撕裂强度降低,另一方面减小了泡孔直径,增加泡孔密度,POE在质量分数30%的时候性能最好,泡孔直径是79.2μm。而随着POE-g-MAH含量的增加,一方面显著提高了发泡材料的拉伸、撕裂强度及耐磨强度,另一方面进一步降低了泡孔直径,增大了泡孔密度。接枝马来酸酐的POE质量分数在30%～40%发泡材料的性能最好,泡孔直径为68.1μm。     

Low frequency viscosities of PS/PMMA/PS-b-PMMA blends

Assuming that the viscosimetric behaviour at low frequencies is mainly determined by the behaviour of the continuous phase, it becomes possible to explain the behaviour of PS/PMMA blends from a limited number of hypotheses. The main hypothesis is that the PMMA layer next to the interface gelifies, while the PS layer next to the interface slips under the influence of a hydrodynamical field. The explanation concurs with all the experimental data which we obtained, regardless of the concentration of PS or PMMA. Moreover the effect of adding a block copolymer PS-b-PMMA can be explained.     

PS/PMMA共混体系的挤出流变行为

利用单螺杆挤出机,配备特殊设计的狭缝模头,在不改变螺杆转速的情况下获得流经口模的不同流量,研究了聚苯乙烯(PS)/聚甲基丙烯酸甲酯(PMMA)共混体系的挤出流变行为。结果表明,PS/PMMA共混物熔体的流变行为和其组分熔体的流变行为类似,都表现出假塑性流体的流动行为;在所研究的组成范围内,共混物熔体的非牛顿指数低于任一组分熔体。随着共混物黏度比的减小,其熔体的非牛顿指数呈下降的趋势;共混物熔体的黏度对加和性法则皆表现为负偏差,表明在界面处具有弱的相互作用。     

Effect of composition on the linear viscoelastic behavior and morphology of PMMA/PS and PMMA/PP blends

Here, the effect of concentration on the morphology and dynamic behavior of polymethylmethacrylate/polystyrene (PMMA/PS), for PS with two different molecular weight, and polymethylmethacrylate/polypropylene (PMMA/PP) blends was studied. The blends concentrations ranged from 5% to 30% of the dispersed phase (PS or PP). The dynamic data were analyzed to study the possibility of inferring the interfacial tension between the components of the blend from their rheological behavior using Palierne [Palierne JF. Rheol Acta 1990;29:204-14] [1] and Bousmina [Bousmina M. Acta 1999;38:73-83] [2] emulsion models. The relaxation spectrum of the blends was also studied. The dynamic behavior of 85/15 PS/PMMA blend were studied as a function of temperature. It was possible to fit both Palierne and Bousmina's emulsion models to the dynamic data of PMMA/PS blends, to obtain the interfacial tension of the blend. This was not the case for PMMA/PP. The relaxation spectrum of both blends was used to obtain the interfacial tension between the components of the blends. The values of interfacial tension calculated were shown to decrease when the concentration of the blends increased. It was shown using morphological analysis that this phenomenon can be attributed to the coalescence of the dispersed phase during dynamic measurements that occurs for large dispersed phase concentration. When the ‘coalesced’ morphology is taken into account in the calculations the interfacial tension inferred from rheological measurement did not depend on the concentration of the blend used. The values of interfacial tension found analyzing the dynamic behavior of one of the PMMA/PS blend were shown to decrease with temperature.     

Effects of annealing on morphology of polymer/polymer (PS/PMMA) blend; a fluorescence study

Steady state fluorescence (SSF) technique conjunction with optical microscopy were used to study the morphology of polystyrene (PS)/poly(methyl methacrylate) (PMMA) blend upon annealing above glass transition in elevated time intervals. The PS/PMMA blends were prepared from dissolution of pyrene (P) and naphthalene (N) labeled PS and PMMA particles, respectively. Monte Carlo simulations were performed to model the N and P fluorescence intensities (I_N and I_P), using photon diffusion theory. Number of N and P photons (N_N and N_P) emerging from the front surface of the blend are calculated when only N is excited, where N_P photons are combined of photons from radiative (N_PR) and nonradiative (N_PNR) energy transfer processes. Optical microscopy images were taken at each annealing step to support our findings from fluorescence measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2104–2110, 2006     

Expansion of core–shell PS/PMMA particles

Structured micrometric polystyrene/poly(methyl methacrylate) particles were obtained by suspension polymerization and their expansion behavior was investigated using n‐pentane as blowing agent. The expanded particles presented two distinct microstructures with an outer region (PMMA‐rich shell) composed by cells of about 10 µm while the center of the particle (PS‐rich core) had much larger cells (50–100 μm). The core–shell particles did not expand at 100°C meaning that the PMMA shell hindered the expansion of the particles. Maximum expansion was dependent on the PMMA concentration and also on the heating temperature and the increase in the PMMA molar mass led to a delay in the onset of the process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4521–4527, 2013