有机高分子化的无机微粒对PVC的填充改性

研究了微细SiO2胶囊化的复合无机粒子与聚氯乙烯共混的复合材料的力学性能的变化规律。结果表明：SiO2/HPMC-PMMA(SiO2经SDS预处理）和HPMC－g-PMMA使材料力学性能下降，而SiO2/HPMC-PMMA（未经SDS处理）使材料的力学性能有所提高。经柔性设计后的SiO2/HPMC-PBA/PMMA使材料的冲击强度提高幅度更大。SEM提供的证据也进一步证明了这一结论。     

溶胶-凝胶法聚丙烯酸丁酯/二氧化硅杂化材料弹性体的制备与表征

用丙烯酸丁酯与少量功能单体共聚,合成了分子链侧基带羟基的聚丙烯酸丁酯(PBA)乳液,然后与硅溶胶混合,用溶胶-凝胶法制备了PBA/SiO2杂化材料弹性体;研究了SiO2含量对杂化材料弹性体力学性能及透光率的影响,并用扫描电子显微镜、傅里叶变换红外光谱、差示扫描量热分析和动态力学性能分析对杂化材料弹性体的结构进行了表征。结果表明,PBA/SiO2杂化材料热压后成为一种力学性能优良的具有一定透光率的弹性体。随着SiO2含量的增加,杂化材料弹性体的力学性能提高,透光率和SiO2粒子的粒径增加,PBA基体的玻璃化转变温度和损耗因子下降;PBA共聚物分子链侧基所带羟基与SiO2粒子表面的硅醇基发生了缩合脱水反应,形成了Si—O—C共价键,使PBA基体与SiO2粒子构成的界面结合紧密,从而赋予杂化材料弹性体以优良的性能。     

原位乳液聚合制备的聚丙烯酸丁酯/纳米SiO2复合粒子的形貌和形成机理

通过吸附于水相分散纳米SiO2粒子表面的2,2'-偶氮(2-脒基丙烷)二氢氯化物(AIBA)的引发作用,进行丙烯酸丁酯(BA)的原位乳液聚合,制备聚丙烯酸丁酯(PBA)/纳米SiO2复合乳胶粒.分别采用透射电镜观察复合粒子的形貌,高速离心分离/超声分散和氢氟酸腐蚀表征复合胶乳中PBA乳胶粒与纳米SiO2粒子的结合程度.发现有纳米SiO2粒子聚集于复合乳胶粒表面,复合粒子表面粗糙,呈"草莓形"结构;当复合粒子中SiO2质量分率为14.6%～22.6%时,60%左右的纳米SiO2富集于复合粒子表面,30%左右被包覆在复合粒子内部,另有少量游离于水相.采用原位乳液聚合得到的复合粒子中纳米SiO2与聚合物的结合牢度远大于以AIBA为引发剂合成的PBA乳液与纳米SiO2分散液直接混合所能达到的结合牢度.认为在原位乳液聚合过程中,由于纳米SiO2粒子表面锚固的PBA量的不同,引起SiO2粒子的亲水/亲油性和与PBA的相容性也不相同,导致出现以上的SiO2的分布特性和复合粒子形貌.     

无皂乳液聚合制备SiO_2/PMMA纳米复合胶体微球

采用半连续无皂乳液聚合方法在未经硅烷偶联剂改性的230 nm亲水性SiO2微球表面聚合甲基丙烯酸甲酯(PMMA)壳层,制备以SiO2粒子为核、PMMA为壳层的复合胶体微球。研究微球表面形貌、组成、粒径变化规律,探索聚合反应的成核过程和PMMA进料流量对复合微球粒径的影响。结果表明,在未经硅烷偶联剂改性的纳米SiO2表面可形成稳定规整的PMMA壳层,SiO2/PMMA复合胶体微球球型度接近1.0,单分散性较好,多分散度指数(PDI)小于0.04。聚合反应受甲基丙烯酸甲酯(PMMA)单体含量控制,随着PMMA进料流量增加,乳胶粒子成核过程由均相成核过渡为胶束成核,复合微球粒径加速增大,多分散性增强,其粒径可通过调节PMMA进料流量控制。     

纳米SiO2粒子对PP结晶行为的影响

通过X-射线光电子能谱（XPS）对经偶联剂处理的纳米SiO2粒子（简称烷基化SiO2纳米粒子）和聚甲基丙烯酸甲酯（PMMA）接枝包覆SiO2纳米粒子（简称SiO2-g-PMMA复合纳米粒子）的表面组成进行分析。将纳米SiO2粒子，烷基化SiO2纳米粒子，复合纳米粒子分别与基体PP复合制备复合材料，通过DSC，WAXD和TEM等测试方法详细研究了PP/SiO2复合材料的结晶行为与力学性能，结果发现：纳米SiO2粒子与烷基化SiO2纳米粒子并不改变基体PP的结晶形态，而复合纳米粒子诱发了基体PP的β晶型结晶，复合纳米粒子比较均匀地分散于PP基体中，对复合材料的力学性能有较大的改善。     

ATRP法制备纳米SiO2-g-PBA及其对POM改性

采用原子转移自由基聚合(ATRP)法在纳米二氧化硅(Si02)粒子表面接枝聚丙烯酸丁酯(PBA),产物为纳米siO2-g-PBA,采用透射电镜(TEM)、偏光电子显微镜(PLM)等手段研究了纳米SiO2及纳米SiO2-g-PBA复合粒子的添加对聚甲醛(POM)结晶性能及热稳定性的影响.结果表明.采用ATRP法有少量的PBA接枝了:纳米SiO2表面,且该粒子在POM中分散均匀;纳米SiO2及纳米SiO2-g-PBA复合粒子的添加不改变POM的晶型,但POM的晶粒尺寸变小.a纳米SiO2-g-PBA复合粒于的异相成核作用较纳米SiO2明显;纳米SiO02及纳米Si2-g-PBA复合粒子使POM的结晶温度升高,熔点升高,结晶度升高.纳米SiO2及纳米SiO2-g-PBA复合粒子的添加使得POM的热稳定性得到了提高.且纳米SiO2-g-PBA复合粒子的作用更明显.     

纳米SiO2粒子静电吸附引发剂及引发甲基丙烯酸甲酯乳液聚合

对纳米SiO2粒子静电吸附2,2′-偶氮(2-脒基丙烷)二氯化氢(AIBA)引发剂,进而在其表面引发甲基丙烯酸甲酯乳液聚合而制备聚甲基丙烯酸甲酯(PMMA)/纳米SiO2复合粒子进行了研究.发现当介质pH值高于SiO2粒子等电势点时,纳米SiO2能与AIBA发生静电吸附而锚固上引发剂.使用高速离心分离/紫外分光光度计分析,证明引发剂吸附存在一个稳定上限,在pH=10时为0.067g·(g·SiO2)-1.随着纳米SiO2粒子锚固AIBA量的增加,聚合速率增加,PMMA/纳米SiO2复合粒子的平均粒径变小;乳化剂OP-10用量过大时,复合粒子的胶体稳定性降低.原位乳液聚合得到的PMMA/纳米SiO2复合粒子的典型形态为"草莓"型核壳结构.     

以具有核壳结构的聚丙烯酸酯颗粒增韧环氧树脂胶粘剂

研制了PEA/PMMA~(…)核壳乳胶粒子,并用于改性环氧树脂。SEM照片指出PBA分散相的平均粒径尺寸。力学性能及Tg测试结果表明改性环氧树脂体系的力学性能大幅度提高,而Tg并未降低。PBA/PMMA核壳粒子为环氧树脂有效的增韧剂。     

PBA/SiO_2杂化弹性体材料的性能及表征

以含羟基的乙烯基单体为共聚单体,合成了功能化的聚丙烯酸丁酯（PBA）乳液,以硅溶胶为无机相,用溶胶-凝胶法制备了PBA/SiO2杂化弹性体材料,进行了力学性能研究和结构表征。结果表明,PBA/SiO2杂化材料热压后成为一种力学性能优良的弹性体。扫描电镜和透射电镜分析表明,SiO2粒子均匀分散于PBA基体中,两相结合紧密,无脱落现象发生;结合橡胶分析结果表明,杂化材料热压后,无机相与有机相之间发生缩合反应,形成了共价键,使得两相间的界面结合力增强;TG表明,杂化材料的热稳定性有显著提高。     

PMMA接枝纳米ZnO复合粒子改性PVC塑料性能研究

通过原位聚合将甲基丙烯酸甲酯（MMA）接枝于纳米ZnO表面,制备了PMMA接枝纳米ZnO复合粒子,将其加入聚氯乙烯（PVC） 基体中进行改性。研究了纳米ZnO粒子在PVC基体中的分散性和PVC复合材料的力学性能,探讨了改性纳米ZnO粒子填充PVC材料的抗紫外线性能。结果表明,改性后的纳米ZnO粒子在PVC基体中分散均匀, 提高了纳米ZnO粒子与PVC基体之间的相容性,使改性PVC材料的拉伸强度达到78 MPa,比纯纳米ZnO粒子改性PVC提高了35 %;冲击强度提高了近1倍,达到13.6 kJ/m2;加入改性纳米ZnO粒子的PVC还具有明显的吸收紫外线功能。     

纳米二氧化硅颗粒表面设计及其填充聚氯乙烯复合材料的性能

利用表面原位接枝聚合在纳米二氧化硅颗粒表面引入聚甲基丙烯酸甲酯(PMMA)高分子链段,用共混法制备了nano-SiO2/PVC复合材料,研究了不同界面特性时SiO2/PVC复合材料的力学性能.研究结果表明通过表面原位接枝聚合反应可以在纳米二氧化硅颗粒表面接枝聚甲基丙烯酸甲酯;表面接枝PMMA的nano-SiO2/PVC复合材料在力学和加工性能等方面都优于偶联剂处理和表面未处理样品.在纳米二氧化硅颗粒填充量为0%～8%(wt)时,复合材料的拉伸强度和冲击强度随着填充量的提高先上升后下降,并在4%～6%(wt)达到最大值.经PMMA表面接枝后SiO2/PVC具有更强的界面作用,偶联剂KH570处理的次之,表面未处理样品的最差.     

表面引发活性聚合SiO2/PMMA核壳复合纳米粒子的制备及表征

在乙醇介质中,通过在窄粒径分布SiO2胶体粒子表面上接枝的α-溴代物引发甲基丙烯酸甲酯的原子转移自由基聚合,制备了具有核壳结构的SiO2/PMMA复合纳米粒子.采用FTIR、TGA和Acoustosizer等表征了该核壳结构粒子的结构与性能、粒径和粒径分布.结果表明:PMMA已经成功接枝到SiO2表面,并且其链长约为8...     

改性TiO2在PVC基体中的分散行为研究

通过熔融共混法制备了聚氯乙烯/二氧化钛(PVC/TiO2)复合材料,通过扫描电镜观察TiO2粒子在PVC中的分散状态,并测定了材料的力学性能。结果表明,在粒径一定的条件下,TiO2粒子在PVC中的分散状态及复合材料的力学性能与表面改性方法密切相关;经过钛酸四丁酯偶联剂[Ti(OBu)4]、γ-氨丙基三乙氧基硅烷偶联剂（KH-550）、聚甲基丙烯酸甲酯（PMMA）改性的TiO2粒子能有效提高粒子在塑料中的分散性及冲击强度,当PMMA改性的TiO2粒子添加量为2.5份时,冲击强度提高超过100 %;而经十二烷基磺酸钠（SLS）改性的粒子团聚严重,复合材料力学性能明显下降。     

Acrylonitrile-styrene-acrylate particles with different acrylonitrile contents for improving the toughness of poly(vinyl chloride) resin

Poly(butyl acrylate) grafted styrene and acrylonitrile copolymer (PBA-g-SAN, ASA) with core–shell structures were prepared by emulsion polymerization technology to improve the toughness of the poly(vinyl chloride) (PVC). The mechanical properties of the PVC/ASA blends were investigated. The notch impact strength of the PVC/ASA blend could reach 1200 J/m when the 13 phr ASA was added to the PVC. This was several times more than pure PVC resin. Scanning electron microscopy analysis results indicated that the improvement in impact strength of the PVC/ASA blend was attributed to shear yielding induced by ASA particles. Additionally, subtle changes in the ratio of monomers in the shell layer led to significant fluctuations in the mechanical properties of the composites. Dynamic mechanical analysis showed that the intermolecular interaction forces between ASA particles and PVC resins played a key role in improving the toughness of PVC/ASA blend.     

Synthesis and characterization of poly(butyl acrylate‐co‐ethylhexyl acrylate)/ poly(vinyl chloride)[P(BA‐EHA)/PVC] novel core‐shell modifier and its impact modification for a poly(vinyl chloride)‐based blend

Synthesis of poly(butyl acrylate‐co‐ethylhexyl acrylate)‐core/poly(vinyl chloride)‐shell [P(BA‐EHA)/PVC] used as a modifying agent of PVC via semicontinuous seeded emulsion copolymerization is reported here. Diameter distributions and morphology of the composite latex particles were characterized with the aid of particle size analyzer and transmission electron microscopy (TEM). The grafting efficiency (GE) and grafting ratio (GR) of vinyl chloride (VC) grafted onto the P(BA‐EHA) with varying content of crosslinking agent and core‐shell ratios were investigated. TEM studies indicated that the P(BA‐EHA)/PVC latex particles have core‐shell structure, and the P(BA‐EHA) rubbery particles in blending materials were uniformly dispersed in PVC matrix. Dynamic mechanical analysis (DMA) results revealed that the compatibility between the P(BA‐EHA) and the PVC matrix was significantly improved due to the presence of the P(BA‐EHA)‐grafted‐VC copolymer. The notched impact strength of the blending material with 3 wt% of rubber content was seven times that of the PVC. Linear regressions of mechanical properties as loading of the modifier were made. The resulting data of notched impact strength and elongation at break for the blending materials deviated significantly from regression lines within 3–4.5 wt% of the P(BA‐EHA) content. The PVC blends modified by the modifier exhibited good toughness and easy processability. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Effect of talc/MMA in situ polymerization on mechanical properties of PVC‐matrix composites

In this study, polymethyl methacrylate (PMMA)‐coated talc was produced by the in situ polymerization of methyl methacrylate on the talc surface. The polymerization reaction was performed by both batch and semicontinuous emulsion processes. The polymerization kinetics, particle size and distribution, grafting efficiency, and coated‐talc morphology were systematically investigated. It was found that the talc particles have no effect on the polymerization of PMMA. The PMMA produced was found to cover the talc surface well. However, only a small amount can be grafted onto the talc. The size distribution of talc particles treated by semicontinuous emulsion polymerization is more uniform than by batch polymerization. The treated talc was subsequently used as filler in a poly(vinyl chloride) (PVC) matrix, and mechanical properties of the PMMA‐coated‐talc/PVC composites were studied. Morphological structure of PVC‐matrix composites revealed that the PMMA coating on talc improved the dispersion of talc in the PVC matrix and enhanced the interfacial adhesion between the talc and PVC. The mechanical properties of the composites, especially the impact strength, were found to be improved. There appears to be a critical covering thickness of PMMA on the talc surface for optimum toughening. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2105–2112, 2001     

有机高分子包覆的滑石粉在PVC加工中应用

表面偶联化处理的滑石粉微粒经乳液聚合甲基丙烯酸甲酯接枝共聚物包覆，构成复合粒子。通过红外光谱（FT—IR）、扫描电镜（SEM）等检测表征,确认其核壳聚合物包覆的形态结构，并用于填充聚氯乙烯（PVC）塑料。结果表明，与未经包覆的对照粒子填充PVC材料的性能相比，其填充的PVC拉伸强度、冲击强度得到了大幅提高，包覆的复合粒子可作为新颖的增强增韧改性剂用于PVC电缆料或其他制品中。     

苯乙烯和甲基丙烯酸甲酯梯度共聚物的应用

将用原子转移自由基聚合及连续补加甲基丙烯酸甲酯（MMA）的方法制备的苯乙烯（St）/MMA梯度聚合物P（Pt-t-MMA）作为增容剂应用于聚氯乙烯/苯乙烯-丁二烯-苯乙烯嵌段共聚物（PVC/SBS）和PS/PMMA聚合物合金的增容和改性。扫描电镜结果表明,P（St-t-MMA）可以改善PVC/SBS和PMMA/PS合金的相容性。PVC/SBS合金中加入少量P（St-t-MMA)后,冲击强度从6.0kJ/m^2提高到12.1kJ/m^2,加工流变性能得到了改善。SBS用量也影响PVC/SBS合金的冲击强度。