环氧官能化ABS增韧PBT树脂的性能研究

采用乳液聚合方法合成了甲基丙烯酸环氧丙酯(GMA)共聚的丙烯腈/丁二烯/苯乙烯核壳粒子ABS-g-GMA,用于不同分子量聚对苯二甲酸丁二醇酯(PBT)的增韧。红外光谱证明GMA接枝共聚到了ABS粒子上。DMA测试发现PBT与ABS、ABS-g-GMA之间有一定的相容性。SEM表明ABS-g-GMA均匀分散在不同分子量的PBT树脂中。ABS-g-GMA可以实现对PBT树脂的有效增韧,PBT树脂的分子量越大,增韧效率越高,共混物的断裂伸长率越大。     

游离链段在环氧官能化ABS增韧PBT中的作用研究

采用种子乳液聚合方法,在聚丁二烯(PB)表面接枝苯乙烯(St)、丙烯腈(AN)和甲基丙烯酸环氧丙酯(GMA),合成了具有反应活性的ABS-g-GMA核-壳改性剂;通过超速离心方法将改性剂中的苯乙烯-丙烯腈-甲基丙烯酸环氧丙酯共聚物(SAN-co-GMA)游离链段分离出来,得到了ABS-g-GMA′核-壳改性剂;最后将分离出来的SAN-co-GMA游离链段按照不同用量回加到PBT/ABS-g-GMA′共混物中,研究游离链段的用量对ABS-g-GMA核-壳改性剂增韧聚对苯二甲酸丁二醇酯(PBT)的影响。结果表明,当加入的游离链占ABS-g-GMA′改性剂的2.50%时,PBT/ABS-g-GMA′共混物的冲击强度和断裂伸长率最大,弯曲强度、弹性模量和屈服强度最小;共混物的分散相形态表明游离链段对核-壳粒子在PBT基体中分散的均匀程度影响不大。     

ACR-g-GMA的制备及对PBT的增韧

要采用乳液聚合方法合成了以丙烯酸丁酯(BA)为橡胶相内核,甲基丙烯酸甲酯(MMA)为壳层,并在壳层接枝甲基丙烯酸环氧丙酯(GMA)的核壳结构聚合物(AcR-g-GMA)。用其增韧聚对苯二甲酸丁二醇酯(PBT),制备PBT/ACR-g-GMA合金。用傅立叶变换红外光谱考察接枝聚合物的环氧基团;用电子显微镜观察共混物中粒子分布的微观形态;测试了共混物的力学性能。结果表明:采用乳液聚舍方法能够将GMA接枝到ACR上,GMA可以增强两相间的界面结合力,ACR-g-GMA粒子能有效地增韧PBT。当ACR-g-GMA粒子中GMA的质量分数为3%,m(PBT)/m(ACR-g-GMA)为80/20时,共混物的缺口冲击强度可高达389 J/m。     

ABS-g-GMA增韧聚对苯二甲酸丁二醇酯的研究

用甲基丙烯酸环氧丙酯（（MA）接枝的丙烯腈／丁二烯／苯乙烯（ABs）接枝共聚物（ABS-g-GMA）改善聚对苯二甲酸丁二醇酯（PBT）的缺口冲击韧性。动态力学分析、差示扫描量热分析以及流变性能测试结果表明，GMA引入到ABS中，随GMA含量的增加，PBT与ABS的玻璃化转变温度相互靠近，PBT的熔点降低，共混体系的扭矩、温度提高，这些结果表明GMA提高了PBT与ABS之间的相容性；增容反应导致ABS在PBT基体中均匀、稳定分散，有利于共混物性能的改善；交联反应导致交联聚集网状结构的生成，使共混物性能变差。冲击强度结果表明，1％（质量含量。下同）GMA含量就可以导致PBT／ABS-g-GMA共混物冲击韧性显著改善，当ABS-g-GMA1含量为30％时，共混物冲击强度高达850J／m。     

POE接枝GMA的制备及其增韧PBT的研究

采用熔融接枝法制备聚烯烃热塑弹性体(POE)接枝甲基丙烯酸缩水甘油酯(GMA),将接枝物(POE-g-(GMA-g-St))用于聚对苯二甲酸丁二醇酯(PBT)的增韧改性,研究接枝物含量对PBT/POE-g-(GMA-g-St)共混物力学性能、结构以及熔融结晶行为的影响。结果表明:POE-g-(GMA-g-St)对PBT具有良好的增韧效果,当弹性体中加入25%时,共混物的冲击强度为66.62 kJ/m2。SEM图像显示:作为分散相的接枝物在PBT基体中的尺寸更小且粒径分布更均匀。DSC图像显示出现两个熔融峰且随接枝物含量的增加使其结晶度逐渐降低。     

POE熔融接枝GMA的制备及其增韧PBT的应用研究

采用熔融接枝法制备聚烯烃热塑弹性体(POE)接枝甲基丙烯酸缩水甘油酯(GMA),将接枝物[POE-g-(GMA-g-St))]用于聚对苯二甲酸丁二醇酯(PBT)的增韧改性。研究了接枝物含量对共混物力学性能、结构以及熔融结晶行为的影响。结果表明:POE-g-(GMA-g-St)对PBT具有良好的增韧效果,当加入弹性体30%时,共混物的冲击强度为71.97 kJ/m2。SEM图像显示:作为分散相的接枝物在PBT基体中的尺寸更小且粒径分布更均匀。DSC图像显示出现两个熔融峰且随接枝物含量的增加其结晶度逐渐降低。     

ABS接枝物的制备及其对r-PET/ABS的增容作用

通过反应挤出法制备马来酸酐(MAH)接枝丙烯腈-丁二烯-苯乙烯三元共聚物(ABS)(ABS-g-MAH)和甲基丙烯酸缩水甘油酯(GMA)接枝ABS(ABS-g-GMA),将其用于增容回收聚对苯二甲酸乙二酯(PET)瓶片(r-PET)/ABS共混物,发现能显著提高共混物的冲击强度。ABS-g-MAH的增容效果优于ABS-g-GMA;ABS-g-MAH的接枝率为1.35%,w(ABS-g-MAH)为5%时对r-PET/ABS的增容作用最佳,此时r-PET/ABS/ABS-g-MAH的简支梁缺口冲击强度和无缺口冲击强度比r-PET/ABS分别提高了42%和23%。扫描电子显微镜观察表明,加入ABS接枝物能使ABS在r-PET连续相中的分散更均匀,粒径尺寸更均一。     

POE接枝MA增韧PBT的研究

用熔融接枝法制备的马来酸酐接枝乙烯-1-辛烯共聚物(POE-g-MA)对聚对苯二甲酸丁二醇酯(PBT)的增韧改性,研究了不同接枝率的POE-g-MA对PBT/POE-g-MA共混物力学性能、结构以及熔融结晶行为的影响。结果表明,POE接枝MA后可明显提高POE与PBT的相容性及PBT的冲击性能,但接枝率过高反而会影响界面黏结,使冲击性能降低。     

苯乙烯在POE接枝GMA中的作用及其对增韧PBT效果的影响

采用苯乙烯(St)为辅助接枝单体,在聚烯烃弹性体(POE)上熔融接枝甲基丙烯酸缩水甘油酯(GMA),制备了POE-g-GMA,通过红外光谱表征证实了接枝反应的发生,考察了St的引入对POE-g-GMA接枝率、熔体流动速率以及POE-g-GMA增韧聚对苯二甲酸丁二醇酯(PBT)的影响。结果表明,在m(St)/m(GMA)为1时POE-g-GMA接枝率达到最大值,为1.057%;随着St用量的增加,接枝物的熔体流动速率持续降低;St的引入使POE相区尺寸明显减小,POE分散相与PBT基体间的相容性明显改善,共混物的冲击强度显著提高,PBT得到有效增韧。     

马来酸酐接枝乙烯-辛烯共聚物对聚对苯二甲酸丁二醇酯的增韧作用

研究了马来酸酐接枝乙烯-辛烯共聚物(POE—g—MAH)和POE—g—MAH／聚丙烯(PP)共混物对聚对苯二甲酸丁二醇酯(PBT)的增韧作用。结果表明,POE—g—MAH／PP共混物对PBT的增韧效果优于POE—g—MAH的,POE—g—MAH和PP并用具有显著的协同增韧作用。扫描电镜照片表明,POE—g-MAH／PP共混物增韧PBT具有软壳-硬核结构。     

环氧树脂对聚对苯二甲酸丁二酯共混物的增韧增强研究

利用环氧树脂(EP)与聚对苯二甲酸丁二醇酯(PBT)的相容性,考察了EP对共混物PBT/ABS-gGMA性能的影响。采用动态力学分析仪(DMA)、旋转流变仪、Haake流变仪和扫描电镜(SEM)研究共混物的性能。DMA、DSC和旋转流变仪的测试结果表明PBT与EP是相容的;流变性能测试结果表明EP对PBT/ABS-g-GMA共混体系起到增容作用;SEM观察结果发现少量的EP加入对共混物的相形态没有明显影响,分散相在PBT基体中均匀、稳定分散,而过量的EP使共混物中出现一些较大的相区,分散相发生团聚;力学性能测试结果表明适量的EP就能明显提高共混物的冲击性能,而过量的EP又会使共混物的冲击强度下降。     

Influence of the degree of grafting on the morphology and mechanical properties of blends of poly(butylene terephthalate) and glycidyl methacrylate grafted poly(ethylene‐co‐propylene) (EPR)

Poly(ethylene‐co‐propylene) (EPR) was functionalized to varying degrees with glycidyl methacrylate (GMA) by melt grafting processes. The EPR‐graft‐GMA elastomers were used to toughen poly(butylene terephthalate) (PBT). Results showed that the grafting degree strongly influenced the morphology and mechanical properties of PBT/EPR‐graft‐GMA blends. Compatibilization reactions between the carboxyl and/or hydroxyl of PBT and epoxy groups of EPR‐graft‐GMA induced smaller dispersed phase sizes and uniform dispersed phase distributions. However, higher degrees of grafting (>1.3) and dispersed phase contents (>10 wt%) led to higher viscosities and severe crosslinking reactions in PBT/EPR‐graft‐GMA blends, resulting in larger dispersed domains of PBT blends. Consistent with the change in morphology, the impact strength of the PBT blends increased with the increase in EPR‐graft‐GMA degrees of grafting for the same dispersion phase content when the degree of grafting was below 1.8. However, PBT/EPR‐graft‐GMA1.8 displayed much lower impact strength in the ductile region than a comparable PBT/EPR‐graft‐GMA1.3 blend (1.3 indicates degree of grafting). Morphology and mechanical results showed that EPR‐graft‐GMA 1.3 was more suitable in improving the toughness of PBT. SEM results showed that the shear yielding properties of the PBT matrix and cavitation of rubber particles were major toughening mechanisms. Copyright © 2006 Society of Chemical Industry     

Phase morphology development during processing of compatibilized and uncompatibilized PBT/ABS blends

The development of the multiphase morphology of uncompatibilized blends of poly(butylene terephthalate) (PBT) and acrylonitrile–butadiene–styrene terpolymer (ABS) and PBT/ABS blends compatibilized with methyl‐methacrylate glycidyl‐methacrylate (MMA‐GMA) reactive copolymers during compounding in a twin‐screw extruder and subsequent injection molding was investigated. Uncompatibilized PBT/ABS 60/40 (wt %) and compatibilized PBT/ABS/MMA‐GMA with 2 and 5 wt % of MMA‐GMA showed refined cocontinuous morphologies at the front end of the extruder, which coarsened towards the extruder outlet. Coarsening in uncompatibilized PBT/ABS blends is much more pronounced than in the compatibilized PBT/ABS/MMA‐GMA equivalents and decreases with increasing amounts of the MMA‐GMA. For both systems, significant refinement on the phase morphology was found to occur after the blends pass through the extruder die. This phenomenon was correlated to the capacity of the die in promoting particles break‐up due to the extra elongational stresses developed at the matrix entrance. Injection molding induces coarsening of the ABS domains in the case of uncompatibilized PBT/ABS blends, while the reactive blend kept its refined phase morphology. Therefore, the compatibilization process of PBT/ABS/MMA‐GMA blends take place progressively leading to a further refinement of the phase morphology in the latter steps, owing to the slow reaction rate relative to epoxide functions and the carboxyl/hydroxyl groups. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 102–110, 2007     

Toughening of poly(butylene terephthalate) with epoxy-functionalized acrylonitrile-butadiene-styrene

Glycidyl methacrylate (GMA) functionalized acrylonitrile-butadiene-styrene (ABS) copolymers have been prepared via an emulsion polymerization process. These functionalized ABS copolymers (ABS-g-GMA) were blended with poly(butylene terephthalate) (PBT). DMA result showed PBT was partially miscible with ABS and ABS-g-GMA, and DSC test further identified the introduction of GMA improved miscibility between PBT and ABS. Scanning electron microscopy (SEM) displayed a very good dispersion of ABS-g-GMA particles in the PBT matrix compared with the PBT/ABS blend when the content of GMA in PBT/ABS-g-GMA blends was relatively low (<8 wt% in ABS-g-GMA). The improvement of the disperse phase morphology was due to interfacial reactions between PBT chains end and epoxy groups of GMA, resulting in the formation of PBT-co-ABS copolymer. However, a coarse, non-spherical phase morphology was obtained when the disperse phase contained a high GMA content (≥8 wt%) because of cross-linking reaction between the functional groups of PBT and GMA. Rheological measurements further identified the reactions between PBT and GMA. Mechanical tests showed the presence of only a small amount of GMA (1 wt%) within the disperse phase was sufficient to induce a pronounced improvement of the impact and tensile properties of PBT blends. SEM results showed shear yielding of PBT matrix and cavitation of rubber particles were the major toughening mechanisms.     

Effects of the molecular structure of impact modifier and compatibilizer on the toughening of PBT/SBS/PS‐GMA blends

This work aims at studying the toughening process of poly(butylene terephthalate) (PBT) through its blends with styrene‐butadiene‐styrene block copolymers (SBS), in the presence of poly(styrene‐ran‐glicydil methacrylate) (PS‐GMA) as reactive compatibilizer. High values of impact strength were attained for PBT/SBS blends without the compatibilizer; however, this improvement is achieved for blends with SBS having similar viscosity compared to PBT, at high SBS content (40 wt %) and for blends prepared under specific processing conditions. The efficiency of the in situ compatibilization of PBT/SBS blends by PS‐GMA was found to be strongly dependent on the SBS and PS‐GMA molecular characteristics. Better compatibilizing results were observed through fine phase morphologies and lower ductile to brittle transition temperatures (DBTT) as the interfacial interaction and stability of the in situ formed compatibilizer are maximized, that is, when the miscibility between SBS and PS‐GMA and reaction degree between PBT and PS‐GMA are maximized. For the PBT/SBS/PS‐GMA blends under study, this was found when it is used the SBS with higher polystyrene content (38 wt %) and with longer PS blocks (M_w = 20,000 g mol^?1) and also the PS‐GMA with moderate GMA contents (4 wt %) and with molecular weight similar to the critical one for PS entanglements (M_c = 35,000 g mol^?1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5795–5807, 2006     

On Toughness and Stiffness of Poly(butylene terephthalate) with Epoxide‐Containing Elastomer by Reactive Extrusion

Summary: To obtain a balance between toughness (as measured by notched impact strength) and elastic stiffness of poly(butylene terephthalate) (PBT), a small amount of tetra‐functional epoxy monomer was incorporated into PBT/[ethylene/methyl acrylate/glycidyl methacrylate terpolymer (E‐MA‐GMA)] blends during the reactive extrusion process. The effectiveness of toughening by E‐MA‐GMA and the effect of the epoxy monomer were investigated. It was found that E‐MA‐GMA was finely dispersed in PBT matrix, whose toughness was significantly enhanced, but the stiffness decreased linearly, with increasing E‐MA‐GMA content. Addition of 0.2 phr epoxy monomer was noted to further improve the dispersion of E‐MA‐GMA particles by increasing the viscosity of the PBT matrix. While use of epoxy monomer had little influence on the notched impact strength of the blends, there was a distinct increase in the elastic stiffness. SEM micrographs of impact‐fracture surfaces indicated that extensive matrix shear yielding was the main impact energy dissipation mechanism in both types of blends, with or without epoxy monomer, and containing 20 wt.‐% or more elastomer.

SEM micrographs of freeze‐fractured surfaces of PBT/E‐MA‐GMA blend illustrating the finer dispersion of E‐MA‐GMA in the presence of epoxy monomer.