甲基丙烯酸甲酯-苯乙烯共聚物的合成及对铸模性能的影响

采用悬浮聚合法合成了两种不同分子量的甲基丙烯酸甲酯(MMA)-苯乙烯(ST)共聚物．通过凝胶渗逢色谱和元素分析确定产品为无规共聚物,对可发处理后的共聚物的铸模性能进行测定,并研究了单体残留量对共聚物分子量和结构以及分子量对铸模性能的影响,结果表明,(1)随单体残留量增加,PSMMA共聚物的分子量减小,(2)同一种PSMMA共聚物珠粒,单体残留量不同,其结构也不同,(3)PSMMA共聚物的分子量愈大,发泡剂含量愈高,发泡倍率愈大,成型密度愈小,相应的发气量和灼烧后的残留量愈小．     

悬浮聚合法制备可发性聚苯乙烯/SiO_2气凝胶核壳珠粒

探讨了可发性聚苯乙烯/SiO2气凝胶核壳复合珠粒悬浮聚合的原理、工艺流程,主要原料的配方,产品指标的控制等。     

可发性聚苯乙烯EPS树脂国家标准

>1、范围 本标准规定了可发性聚苯乙烯树脂的产品分类、技术要求、试验方法、检验规则以及标志、包装、运输、储存。 本标准适用于由苯乙烯单体经悬浮法聚合并加有一定量发泡剂的可发性聚苯乙烯树脂(以下简称EPS树脂)。通过发泡成型,其制品应用于保温、隔热、隔音建筑材料、防震包装材料及漂浮制品等。     

氯乙烯与硅氧烷类单体共聚树脂的研究

详细叙述了氯乙烯与硅氧烷类单体的聚合工艺和配方 ,并指出了硅氧烷类单体的选择范围。提供了共聚物氧气透过性的测试方法。     

RAFT聚合制备嵌段聚合物对PP基材涂料附着力的改善

合成了RAFT试剂S-1-十二烷基-S’-(α,α’-二甲基-α"-乙酸)三硫代碳酸酯(DDAATB),并以此种RAFT试剂为链转移剂制备聚丙烯酸均聚物,再以此均聚物为大分子链转移剂,制备了聚丙烯酸-b-聚丙烯酸异冰片酯嵌段共聚物(PAA-b-PIBOA)。以制备的丙烯酸酯嵌段共聚物作为附着力促进剂,与UV树脂复配成UV涂料,考察了添加不同质量分数嵌段共聚物的涂料对PP基材的附着能力的改善,并与CPP进行了比较。研究结果表明,制备的丙烯酸酯嵌段共聚物可有效提高涂层对PP基材的粘附性,PIBOA链段分子量越大,效果越明显;将制备的PAA-b-PIBOA为附着力促进剂,分别添加至以聚酯丙烯酸酯、氯化聚醚为主体树脂的涂料配方中,通过附着力性能测试,发现合成的嵌段共聚物PAA-b-PIBOA能有效提高涂层对PP基材的附着力。     

P(VAc-MMA-DM)阳离子聚合物乳液的合成及其在造纸增强中的应用

以醋酸乙烯酯(VAc)、甲基丙烯酸甲酯(MMA)和甲基丙烯酸二甲胺乙酯(DM)为原料,采用无乳化剂乳液聚合法合成出了一系列VAc-MMA-DM阳离子共聚物乳液,测定了此乳液的转化率和稳定性,找到了合成最稳定且转化率最高的VAc-MMA-DM阳离子共聚物乳液的配方和条件;由电镜测得此乳液为球形粒子,粒径约为0.1 μm.将VAc-MMA-DM阳离子共聚物乳液加到竹浆或纸浆中,通过对纸张的环压强度、耐破度、撕裂度等的测定,发现当乳液的用量为1.0%时,其增强性能最好.     

P(St-BA-AA)三元共聚物纳米微孔乳胶粒子的制备

以P(St-BA)二元共聚物乳胶作种子乳液,采用乳液聚合法制备得到P(St-BA-AA)三元共聚物乳胶体系.通过分步调节碱和酸度,并在高温条件(90 ℃)下进行酸碱处理,首次制得P(St-BA-AA)三元共聚物纳米微孔乳胶粒子.通过TEM、SEM观察其形态与表面形态,确认微孔结构在乳胶粒子内部形成.依据成孔机理,确认本体系的最佳酸碱处理温度应该高于其玻璃化转变温度Tg.     

新型塑料阻燃剂的合成及其性能研究

将石墨进行氧化处理得到氧化石墨(GO),以甲醛、尿素及GO为原料,通过两步反应合成了GO-MUF新型阻燃剂,用红外光谱确定了化合物的化学键,研究了阻燃可发性聚苯乙烯(EPS)的阻燃性能。结果表明:当阻燃剂用量为25%时,阻燃EPS的氧指数和垂直燃烧等级分别达到36.6%和V-0级。此时,阻燃EPS的阻燃性能最佳。     

具有pH响应性和成纤性的丙烯腈与丙烯酸共聚物的结构

利用丙烯腈(AN)与丙烯酸(AA)单体的化学性质及单体的活性不同,AA采用不同投料方式,制备了具有pH响应性与成纤性的丙烯腈/丙烯酸共聚物[P(AN-co-AA)],通过红外、液体核磁、元素分析等测试手段研究了共聚物结构特点。结果表明,AA与AN单体物质的量比为20∶80时,聚合物具有良好的pH响应性与成纤性;不同投料方式的共聚物中羰基与氰基含量的比值都随着反应进行呈增长趋势,一次性投料更大;分批投料共聚物分子链易形成嵌段结构,表现出良好的pH响应性及较好的力学性能。     

玉米秸秆纤维发泡聚苯乙烯缓冲包装材料及其性能的研究

利用质轻环保和廉价易得的玉米秸秆纤维与可发性聚苯乙烯为原料,开发制备了玉米秸秆纤维缓冲包装材料.通过大量实验与分析确定了制备材料的工艺与实验条件;研究了玉米秸秆纤维粒度、用量、表面处理与可发性聚苯乙烯预发条件、熟化条件对材料密度、强度的影响;对衬垫的静、动态缓冲性能和回弹性进行了测试分析,并与ELDPE、EPS进行对比分析,得到此缓冲材料的缓冲性能的基本特征.     

偏氯乙烯共聚物颗粒发泡能力的影响因素

以1-氟-1,1-二氯乙烷(HCFC-141b)作发泡剂,研究了偏氯乙烯(VDC)共聚物颗粒的发泡能力、中空颗粒的泡孔结构及发泡倍率。实验发现,VDC-甲基丙烯酸甲酯(MMA)共聚物的发泡能力较强,而VDC-丙烯腈(AN)共聚物颗粒很难发泡,当引入第三单元苯乙烯(St)后可改善其发泡性能。VDC—AN—St共聚物颗粒的发泡倍率随着发泡剂浓度的增加或发泡温度的提高而先增加后减小,气泡将随着发泡温度的提高而最终全部破裂塌陷。由破泡和扩散造成的发泡剂损失对VDC共聚物颗粒发泡能力的影响已不能忽略。     

An epoxy resin copolymer with zero shrinkage

Epoxy resin copolymer with zero shrinkage can be obtained by copolymerizing epoxy resin E51 with the expanding monomer of 3,9-di(5-norbornene-2,2)-1,5,7,11 -tetraoxaspiro[5,5]undecane (NSOC). The volume changes of an epoxy resin copolymerized with various amounts of NSOC during cure was measured with a dilatometer. The epoxy copolymer giving zero shrinkage was an epoxy resin with a E51:NSOC ratio equivalent to 5.881. This epoxy resin copolymer with zero shrinkage has been used as an adhesive to join the optical parts of a large optical telescope.     

Epoxy resin copolymer with zero shrinkage

Thermal gravimetry, differential scanning calorimetry, stress-strain and dynamic mechanical testing were performed for pure epoxy resin and epoxy copolymers. Shrinkage, equal density or expansion was obtained by copolymerizing epoxy resin with various amounts of the expanding monomer norbornene spiro-orthocarbonate (NSOC). The glass-transition temperature, thermal-degradation temperature and fracture strength decreased with the introduction of NSOC, indicating that the effect of chain structure on the physical properties of epoxy copolymer was more than that of volume expansion arising from the ring-opening polymerization of expanding monomer NSOC.     

Fast thermoresponsive BAB-type HEMA/NIPAAm triblock copolymer solutions for embolization of abnormal blood vessels

Thermoresponsive BAB-type HEMA/NIPAAm triblock copolymers (A = NIPAAm, B = HEMA) were prepared by atomic transfer radical polymerization (ATRP). BAB1-6 with shorter PNIPAAm blocks failed to form stable gel; while a relatively stable gel could be achieved by BAB1-8 with longer PNIPAAm blocks when copolymer aqueous solution was heated up. Introducing radiopaque agent (RA) was shown to slightly increase the transition temperature and gelation time, but the gelling ability was strengthened due to slightly weakening dehydration of copolymer in the mixture of water and RA. BAB1-8 aqueous solution about 5 wt% in the presence of RA was demonstrated to successfully occlude the cerebral rete mirabiles (RMs) and renal arteries of pigs. Within 3-month surgery, no recanalization was observed and the embolized kidney shrank considerably. Histological assay of embolized kidney demonstrated interstitial fibrosis and calcification as well as the thickening of renal small artery. This temperature sensitive copolymer with well-defined architecture holds a great potential as an embolic agent for treating arteriovenous malformations (AVMs) and renal disease due to the design flexibility of ATRP.     

Morphological analysis of self-assembled SIS block copolymer matrices containing silver nanoparticles

The intrinsic ability of block copolymers to self-assemble at nanoordered level into different nanoscale structures has been used in this study to obtain nanocomposites. Ordered architectures of silver nanoparticles confined in a poly(styrene-b-isoprene-b-styrene) (SIS) block copolymer matrix have been generated. Both cetyl trimethylammonium chloride (TMAC) and dodecanethiol (DT) were used as surfactants to obtain dispersed nanocomposite films. Morphologies generated in Ag/SIS nanocomposites, detected through atomic force, resulted to be more dependent on the amount of silver nanoparticles than on the other variables chosen in the present study such as amount and type of surfactant and preparation parameters. The experimental observations are consistent with phase diagram predictions obtained for hybrid systems composed of block copolymers and nanoparticles.     

Influence of interfacial modification on the thermal conductivity of polymer composites

In this study, the influence of modifying ZnO filler with surface-treating agents on the thermal conductivity of the ethylene-vinyl acetate copolymer (EVA) composites was reported. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were applied to analyze the surface modification of ZnO filler and the fractured surface morphology of the EVA–ZnO composites. The test results indicated that surface-treating ZnO filler with the valid modifying agents (stearic acid, OL-AT16, KH-560, or NDZ-132) at right dosage and treating temperature, the thermal conductivity of the EVA–ZnO composites can be enhanced effectively on account of reducing the interfacial phonon scattering; while the dosage of modifying agents exceed a right amount, the thermal conductivity of EVA–ZnO composites modified with the small-molecule treating agents (F-1, n-Octylic acid, or stearic acid) descend more evidently with the dosage increase.     

Fire-resistant nonwovens of EVOH and PET treated with amorphous sodium polyborate

Nonwovens made of poly(ethylene terephthalate) (PET) and ethylene–vinyl alcohol copolymer (EVOH) are found to become highly fire resistant by treating with amorphous sodium polyborate (SPB). The fire-resistant nonwovens with 10-mm thickness show a gradual temperature increase up to 127 °C and no hole, when their back sides are fired with a gas burner for 12 min. The analysis using the EPMA and the DTA/TG indicates that the SPB foam promotes the formation of char (carbon) layer, and that the char layer together with the SPB foam insulates inside from the oxygen and the heat.     

导电炭黑改性PE-RT抗静电复合材料的形貌与性能

以耐热聚乙烯(PE-RT)管材料为基体,以乙烯-醋酸乙烯共聚物(EVA)载体导电炭黑母粒(记作CBE)为导电介质,配以3.86wt%的聚乙烯-辛烯共聚弹性体(POE),采用双螺杆挤出工艺制备了具有导电网状结构形貌的PE-RT抗静电管材料,降低了复合体系的逾渗阈值,并将其与添加导电炭黑(记作CB)的体系进行对比,研究了CB/PE-RT和CBE/POE/PE-RT复合体系的导电性能、微观形貌、流变性能、力学性能及热稳定性能。结果表明:POE和EVA可以产生协同作用,POE的加入改变了PE-RT与EVA的黏弹性差异,EVA在基体中达到逾渗而形成连续的网络结构。CB优先分散在黏度低、极性较高的EVA相中,且POE能够抑制CB由EVA相向PERT相的迁移,CB在EVA相中容易达到逾渗,最终由于双逾渗作用而形成导电网络结构。CB能够提高PE-RT的结晶性能及CBE/POE/PE-RT复合体系的热稳定性能,且CB对CBE/POE/PE-RT复合体系的力学性能影响较小,在一定程度上解决了目前填充型导电体系中导电性能与力学性能之间的矛盾,并且POE对复合体系起到了增塑作用,保持了PE-RT管材可弯曲的优点,拓展了塑料管材的应用范围。     

Nanocomposites based on MWCNT and styrene–butadiene–styrene block copolymers: Effect of the preparation method on dispersion and polymer–filler interactions

Composites of Kraton-D® 1102 BT (a styrene–butadiene–styrene block copolymer) and multi-walled carbon nanotubes (MWCNTs) were prepared by melt mixing. The composites were characterized by electrical conductivity measurements (Coleman’s method), mechanical properties (DMA and stress–strain tests), thermal stability (thermogravimetry) and morphology of dispersion (SEM). Finally, the resulting composites were compared with those made by the solution casting method. The results showed a strong influence of the preparation methodology on the final properties of the composites due to changes in morphology. Composites prepared by casting showed a higher electrical conductivity than extruded ones; the composites with 6 wt.% of MWCNT prepared by extrusion presented conductivity of the same order of magnitude as the composite with 1 wt.% of MWCNT prepared by casting – 10⁻³ to 10⁻⁴ S cm⁻¹. However, the extruded samples presented better mechanical properties than the casting ones.     

Growth of calcium carbonate on non-covalently modified carbon nanotubes

The crystallization of calcium carbonate was investigated on pristine and non-covalently modified carbon nanotubes (CNTs) using the vapor diffusion technique in a calcium chloride solution. Non-covalent modification was accomplished by treating the carbon nanostructures with the amphiphilic copolymer poly(isoprene-b-acrylic acid). Calcium carbonate crystals grown on the surface and in the interstitial channels of CNT buckypapers were observed in both cases. Scanning electron microscopy analysis of the untreated CNTs showed the characteristic rhombohedral morphology of calcite crystals, while in the case of modified material spherical and ellipsoidal crystals, consisted of nanocrystallites, were observed. X-ray diffraction analysis showed the presence of calcite crystals in both cases.