PVC/MBS共混物的形态及力学性能

采用种子乳液聚合方法,在聚丁二烯乳胶粒子上接枝甲基丙烯酸甲酯（MMA）和苯乙烯（St）,制得MBS核壳接枝共聚物,并将其作为增韧剂与聚氯乙烯（PVC）共混制备PVC/MBS共混物。考察了接枝不同MMA和St含量的MBS在PVC中的分散状态及其对PVC/MBS共混物力学性能。结果表明,当MBS壳层中MMA含量增加时,MBS粒子在PVC基体中的分散状态被改善;PVC/MBS共混物的冲击强度随之增加,冲击强度最高时为1117.74 J/m;当MBS中接枝少量St时,PVC/MBS共混物呈现韧性断裂,冲击值最高时为1039.33 J/m;当MBS接枝大量St时,会产生内包容现象,不利于提高PVC共混物的冲击强度。     

PMMA/SAN/ABS共混物的结构与性能研究

采用乳液聚合技术合成丙烯腈-丁二烯-苯乙烯(ABS)接枝粉料,将制得的ABS接枝粉料与聚甲基丙烯酸甲酯(PMMA)/苯乙烯-丙烯腈共聚物(SAN)熔融共混,制备透明ABS树脂。研究了体系橡胶含量,接枝粉料壳层组成,基体组成对透明ABS树脂结构与性能的影响。结果表明,随着体系橡胶含量的增加,共混物的冲击强度增大,透光率略有降低;壳层组成为75/25的共混物具有较高的韧性和透明性;随着基体PMMA/SAN组成的增加,共混物的冲击强度基本不变,而透光率先增大后减小。透射电子显微镜(TEM)研究表明,壳层组成为75/25的橡胶粒子能均匀地分散在基体中。     

新型核-壳改性剂N-AIM对PMMA性能的影响

通过乳液聚合方法制备了不同橡胶粒径和橡胶相组成比的新型核-壳丙烯酸酯类抗冲改性剂（N-AIM）,将其与聚甲基丙烯酸甲酯（PMMA）进行熔融共混,得到了PMMA/N-AIM共混物。对PMMA/N-AIM共混物的形态结构、冲击性能和光学性能分别进行了考察。通过透射电镜（TEM）分析表明,橡胶粒径为100 nm时改性剂在基体中发生聚集,大于100 nm时均可均匀分散在基体中;冲击测试结果表明,随着N-AIM橡胶粒径的增加,共混物的冲击强度先增大后减小;光学测试表明橡胶组成比影响共混物的光学性能。     

MBS对PBT/PC共混体系性能的影响

研究了甲基丙烯酸甲酯-丁二烯-苯乙烯接枝共聚物(MBS)作为抗冲击改性剂,对聚对苯二甲酸丁二醇酯/聚碳酸酯(PBT/PC)共混体系力学性能和耐热性的影响,并用扫描电子显微镜对共混物的亚微观形态结构进行了分析.结果表明:MBS的加入改善了PBT/PC共混体系的加工流动性能和外观;随着MBS用量的增加,PBT/PC共混体系的冲击强度不断增大,拉伸强度和耐热性下降,但耐热性下降幅度较小.     

PVC/MBS共混物的断裂研究

采用吴康理论(Vu-Khanh-plot)与扫描电子显微镜照片、冲击强度测试数据相结合,研究聚氯乙烯(PVC)/甲基丙烯酸甲酯-丁二烯-苯乙烯(MBS)三元共聚物的裂纹引发断裂能(Gi)与冲击强度的关系.随着增韧剂MBS含量的增加, PVC/MBS共混物的冲击强度提高, Gi由纯PVC的0.32 kJ/m2增加到4.06 kJ/m2.同时, Gi和冲击强度也随MBS粒径的增大而增大.因此, PVC/MBS共混体系的冲击强度随着Gi的增加而增大.     

核-壳结构粒子MBS增韧聚乳酸的性能研究

采用乳液聚合法合成核-壳结构粒子甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS),进一步对聚乳酸(PLA)进行增韧改性,并以甲基丙烯酸甲酯-甲基丙烯酸缩水甘油酯共聚物P(MMA-co-GMA)作为共混体系的相容剂。通过力学性能测试、动态热机械分析仪、透射电子显微镜、扫描电子显微镜等手段研究了该共混体系的力学性能和微观形态。结果表明,随着MBS含量的增加,共混物的冲击强度显著提高,屈服应力逐渐降低;相容剂P(MMAco-GMA)的引入没有提高共混物的冲击性能,但是显著提高了拉伸强度。DMA结果表明,随着P(MMA-co-GMA)中GMA含量的增加,PLA的玻璃化转变温度逐渐上升,MBS壳层的玻璃化转变温度逐渐降低;TEM测试发现P(MMAco-GMA)加入后,核壳粒子在PLA中分散得更加均匀。对形变区的SEM观察发现MBS橡胶粒子发生空洞化,基体发生剪切屈服。     

PVC/α-MSAN/ASA共混物的结构与性能研究

采用乳液聚合技术合成了一系列不同核壳比的丙烯酸丁酯-苯乙烯-丙烯腈接枝共聚物(ASA)和组成为69/31的α-甲基苯乙烯-丙烯腈共聚物(α-MSAN)。将ASA接枝共聚物与聚氯乙烯(PVC)和α-MSAN熔融共混制备了PVC/α-MSAN/ASA共混物,利用扫描电子显微镜(SEM)和差示扫描量热仪(DSC)对该共混体系的性能与形态进行了表征。结果表明:随着体系中橡胶含量的增加,PVC/α-MSAN/ASA共混物的冲击强度先增大后减小,拉伸强度则逐渐降低,其中橡胶含量为15%的共混物具有较高的韧性;当ASA接枝共聚物的核壳比逐渐增大时,共混物的冲击强度先增大后减小,而拉伸强度基本不变;此外,共混试样的断面形态与其力学性能相符。     

PC/ABS共混改性研究

研究了甲基丙烯酸甲酯/丁二烯/苯乙烯共聚物(MBS)作为相容剂对聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯共聚物(ABS)共混体系相容性、力学性能、形态结构以及动态力学性能的影响.结果表明,随着MBS添加量的增加,PC/ABS的缺口冲击强度和断裂伸长率呈先增大再减小的趋势,拉伸强度和弯曲强度都呈下降趋势;加入MBS后,PC/ABS的分散相粒径明显减小,PC与ABS两相的玻璃化转变温度相互靠拢,因而PC/ABS的相容性得到显著改善.     

SAN和MBS对高光免喷涂PMMA合金的影响研究

以苯乙烯-丙烯腈共聚物/聚甲基丙烯酸甲酯(SAN/PMMA)共混物为研究对象,考察了SAN和甲基丙烯酸甲酯-丁二烯-苯乙烯(MBS)改变对共混物力学性能、光学性能和微观结构的影响。研究结果表明:SAN的添加可以显著改变合金材料的性能,其加入量在20～25份时,综合性能最佳。MBS可以显著提高PMMA合金的冲击强度,但随着添加量的提高,光泽度也会下降。     

接枝率对尼龙11／POE／POE—g—MAH韧性的影响

研究了含不同马来酸酐接枝率的POE-g-MAH对尼龙11/POE/POE/-g-MAH（POE为乙烯-辛烯共聚物）共混物的影响,考察了共混物的缺口冲击强度。结果表明：增加POE-g-MAH的用量可提高共混物的缺口冲击强度;共混物缺口冲击强度与POE的马来酸酐接枝率密切相关,缺口冲击强度随着接枝率的增大而增大;共混物的缺口冲击强度和马来酸酐接枝率之间的变化关系在较宽的温度范围内（-40℃-25℃）存在。     

The toughness and morphology of (chlorinated poly[vinyl chloride])/(methyl methacrylate‐butadiene‐styrene) blends

A series of methyl methacrylate‐butadiene‐styrene (MBS) graft copolymers were synthesized via seeded emulsion polymerization techniques by grafting styrene and methyl methacrylate on poly(butadiene‐co‐styrene) (SBR) particles. The chlorinated poly(vinyl chloride) (CPVC)/MBS blends were obtained by melting MBS graft copolymers with CPVC resin, and the effect of the core/shell ratio of MBS graft copolymer and SBR content of CPVC/MBS blends on the mechanical properties and morphology of CPVC/MBS blends was studied. The results showed that, with the increase in the core/shell ratio, the impact strength of the blend increased and then decreased. It was found that, when the core/shell ratio was 50/50, the impact strength was about 155 J/m, and the tensile strength evidently increased. The toughness of the CPVC/MBS blend was closely related to the SBR content of the blend, and with the increasing of SBR content of blend, the impact strength of the blend increased. The morphology of CPVC/MBS blends was observed via scanning electron microscopy. Scanning electron microscopy indicated that the toughness of CPVC/MBS blend was consistence with the dispersion of MBS graft copolymers in the CPVC matrix. J. VINYL ADDIT. TECHNOL., 22:501–505, 2016. © 2015 Society of Plastics Engineers     

Comparison of some butadiene-based impact modifiers for polycarbonate

The relationship of blend morphology to deformation mechanisms and notched Izod impact strength was studied with three butadiene-based impact modifiers for polycarbonate (PC). The impact modifiers were a linear polybutadiene (PB), a styrene–butadiene–styrene block copolymer (SBS), and a structured latex particle having a PB core and methyl methacrylate/styrene shell (MBS). The particle-size distribution in the blends was determined from transmission electron micrographs (TEM). Fractographic analysis combined with TEM examination of thin sections from impacted specimens provided insight into the failure mechanisms. Good impact was achieved with PC/MBS blends when cavitation of the core–shell particles relieved triaxiality and enabled the matrix to fracture by the plane stress ductile tearing mode that is characteristic of thin PC. The best impact properties were obtained with PC/SBS blends when the modifier was dispersed as aggregates of small particles. Cavitation at the weak internal boundaries relieved triaxiality, but subsequent coalescence of cavitated particles during ductile drawing of the matrix created critical size voids and the resulting secondary cracks reduced the toughness of the blend. In general, PB did not significantly enhance the impact strength of PC. © 1994 John Wiley & Sons, Inc.     

MBS核-壳粒子的内部结构对MBS/PVC光学性能的影响

以乳液聚合的方法合成了具有核-壳结构的MBS树脂。恒定MBS中M/B/S的比例为30/42/28,通过采用不同的引发体系及加料方式制备不同内部结构的橡胶粒子。将MBS树脂与聚氯乙烯（PVC）共混,研究了橡胶粒子的内部结构对共混物透光性的影响。用透射电子显微镜对共混物的形态进行了研究,MBS粒子分别具不同的包容物结构。研...     

Solvent cast blends of PMMA microspheres in bisphenol-A-polycarbonate

Abstract

Transparent films of bisphenol-A-polycarbonate (PC), poly (methyl methacrylate) (PMMA) microspheres and their blends at various compositions were prepared by solution casting using methylene chloride (MC) as a solvent. The structural, morphological and thermal properties were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry and thermogravimetric analysis. It was obvious that all the characteristic absorption bands could be found in the IR spectra of PC/PMMA blends, but different in the strength. From the SEM images, a co-continue morphology was observed in the PC/PMMA blends when the PMMA content was above 80wt%, indicating the existence of special interaction between PC and PMMA microspheres. Differential scanning calorimetry results showed a single glass transition temperature (T_g) only for 10%PC/90%PMMA blends because of the better dissolution of PC in PMMA than PMMA in PC. Thermogravimetric analysis thermograms showed that the thermal stability of PC/PMMA blends increased with increasing PC content, which was due to the better thermal stability of PC.     

Phase morphology and dynamic mechanical behavior for MIS toughened polyvinyl chloride

Graft copolymers of isoprene (Is), styrene (St), and methyl methacrylate (MMA) monomers (MIS) with typical core–shell structure were synthesized by seed emulsion polymerization and used as a toughening agent for preparation of polyvinyl chloride (PVC)/MIS blends. The St and MMA monomers were separately grafted on the cross‐linked poly‐isoprene rubber core. The toughness, sub‐micro‐morphology, and dynamic mechanical behavior of the blends were characterized by impact machine, scanning electron microscopy (SEM), and dynamic mechanical analyzer. The results showed that the impact strength of the blends was optimized when the content of MIS in PVC/MIS blends was kept at a constant value of 8 wt %, while the content of Is in MIS was 70 wt %. SEM morphologies of impact fractured surface showed that the PVC/MIS blends were typical ductile fracture because of the toughness effect of rubber particles, which correlated well with the mechanical properties. Under the same rubber content condition, the curves of the dynamic mechanical behavior of MIS toughened PVC blends appeared a more obvious rubber peak, indicating that the rubber content of MIS was higher than that of methyl methacrylate–butadiene–styrene (MBS), which explained the better toughening effect of MIS compared with MBS. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

抗聚结MBS的制备及性能

通过分子结构设计,合成了一系列提高MBS粉末特性的包裹剂,研究了抗聚结新型MBS的制备工艺以及包裹剂化学结构对MBS粉末特性及PVC／MBS共混物力学性能的影响。结果表明,加入包裹剂后,MBS粉末流动性及其堆积密度均有较大提高,而且显著提高PVC／MBS共混物的抗冲强度和抗拉强度。     

Thermal and mechanical properties of poly(methyl methacrylate) and ethylene vinyl acetate copolymer blends

A series of poly(methyl methacrylate) (PMMA) blends have been prepared with different compositions viz., 5, 10, 15, and 20 wt % ethylene vinyl acetate (EVA) copolymer by melt blending method in Haake Rheocord. The effect of different compositions of EVA on the physico‐mechanical and thermal properties of PMMA and EVA copolymer blends have been studied. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) has been employed to investigate the phase behavior of PMMA/EVA blends from the point of view of component specific interactions, molecular motions and morphology. The resulting morphologies of the various blends also studied by optical microscope. The DSC analysis indicates the phase separation between the PMMA matrix and EVA domains. The impact strength analysis revealed a substantial increase in impact strength from 19 to 32 J/m. The TGA analysis reveals the reduction in onset of thermal degradation temperature of PMMA with increase in EVA component of the blend. The optical microscope photographs have demonstrated the PMMA/EVA system had a microphase separated structure consisting of dispersed EVA domains within a continuous PMMA matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) blends

The grafting of the methyl methacrylate (MMA) monomer onto natural rubber using potassium persulfate as an initiator was carried out by emulsion polymerization. The rubber macroradicals reacted with MMA to form graft copolymers. The morphology of grafted natural rubber (GNR) was determined by transmission electron microscopy and it was confirmed that the graft copolymerization was a surface‐controlled process. The effects of the initiator concentration, reaction temperature, monomer concentration, and reaction time on the monomer conversion and grafting efficiency were investigated. The grafting efficiency of the GNR was determined by a solvent‐extraction technique. The natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) (NR‐g‐MMA/PMMA) blends were prepared by a melt‐mixing system. The mechanical properties and the fracture behavior of GNR/PMMA blends were evaluated as a function of the graft copolymer composition and the blend ratio. The tensile strength, tear strength, and hardness increased with an increase in PMMA content. The tensile fracture surface examined by scanning electron microscopy disclosed that the graft copolymer acted as an interfacial agent and gave a good adhesion between the two phases of the compatibilized blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 428–439, 2001     

Poly(methyl methacrylate) toughened by ethylene‐vinyl acetate copolymer: Physico‐mechanical,thermal, and chemical properties

Blends of poly(methyl methacrylate) (PMMA) with different composition viz., 5, 10, 15, and 20 wt % of ethylene‐vinyl acetate (EVA) copolymer were prepared by extrusion in a corotating twin screw extruder. These prepared PMMA/EVA blends have been characterized for physicomechanical properties such as density, surface hardness, izod impact strength, tensile strength, tensile elongation, and tensile modulus. The chemical aging and heat aging tests were performed on the blends by exposing them to different chemical environments and to 80°C for 168 h respectively. The influence of chemical aging and heat ageing on the mechanical performance of PMMA/EVA blends has been studied. The PMMA/EVA blends were also characterized for thermal properties such as vicat softening point (VSP) and melt flow index (MFI). That means significant improvement in impact strength of PMMA was noticed after incorporation of EVA into PMMA matrix and it lies in the range 19.1–31.96 J/m. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007