尼龙11/POE共混物的形态与力学性能

采用动态力学分析(DMTA)和扫描电镜(SEM)等方法研究了相容剂乙烯辛烯共聚物接枝马来酸酐聚合物(POE-g-MAH)对尼龙11(PA11)共混体系力学性能及共混物形态的影响。结果表明,混合弹性体中m(POE-g-MAH)/m(POE)=2∶1时,PA11共混物的缺口冲击强度达到81.2 kJ/m2;共混物缺口冲击强度对MAH接枝率敏感;加入混合弹性体,共混体系分子间的作用力增大,损耗峰向高温方向移动,Tg升高;PA11与POE各个共混体系的β松弛峰高显著低于纯PA11的,加入POE和POE-g-MAH可有效降低PA11的吸水性;POE-g-MAH可显著改善PA11/POE共混材料的相容性,使分散相尺寸减小,分布均匀,且材料缺口冲击强度显著增大。     

动态保压注射成型中POE-g-MAH 对PA1010-PP 共混物的增容作用

以马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)作为增容剂, 采用熔体共混的方法制备了PA1010-PP共混物, 通过扫描电镜(SEM)、 力学性能和差示扫描量热(DSC)测试, 研究了动态保压注射成型中POE-g-MAH对PA1010-PP共混物的增容作用。力学性能测试结果表明, 在注射成型过程中施加剪切应力, 明显提高了共混物的拉伸和冲击性能。SEM结果表明, 剪切诱导制品产生多层次结构, 而且分散相相区尺寸显著减小, 分散更趋均匀, 相界面更加模糊。DSC结果表明, 剪切应力作用下, 当POE-g-MAH的质量分数达到15%时, PP出现2个结晶峰, 即出现异相成核结晶和均相成核结晶, PP均相成核结晶的出现从另一个方面表明动态试样中分散相PP尺寸小于静态试样。剪切应力作用下增容作用的提高归因于剪切应力作用下独特相形态的形成。      

POE/PA共混物性能的分子动力学与介观动力学模拟

为了预测聚烯烃弹性体(POE)与不同聚酰胺(PA6、PA11和PA1010)的相容性及共混物的力学性能和介观形貌,采用分子动力学(MD)和介观动力学(MesoDyn)模拟方法对不同种类的POE/PA共混物进行了研究。结果表明,3种共混体系中PA11/POE共混物的拉伸模量、体积模量及剪切模量都较小,韧性比较好,力学性能和结合能最好;MesoDyn模拟结果表明,PA11与POE相容性最好。本模拟方法可以作为预测聚合物共混物性能的有利工具,也可以为高聚物配方设计提供理论参考。     

增韧PA1010的力学性能及熔融与结晶行为

采用熔融共混法制备了PA1010/纳米橡胶/POE-g-MAH共混物,测试了共混材料的力学性能,用DSC法研究了熔融和结晶行为.结果表明,共混物的冲击强度显著提高,在纳米橡胶质量含量为10%时达到极大值.纳米橡胶并未降低PA1010的拉伸强度,加入POE-g-MAH后略有降低.共混物的熔融过程呈现双峰,纳米橡胶的加入提高了高温峰的熔融焓.纳米橡胶促进了共混物结晶峰向高温区移动.     

环氧树脂低聚物原位增容PA66/TLCP共混物

用环氧树脂低聚物作界面增容剂,熔融挤出法制备了PA66/TLCP共混物。通过拉伸、弯曲等力学性能测试并结合热失重(TG)分析,结果表明:环氧树脂低聚物增容后的共混物力学性能、热稳定性均有显著提高。共混物断面SEM扫描结果表明,由于环氧树脂低聚物界面增容作用,分散相TLCP在基体PA66中的分散性提高并且相畴尺寸减小。加工流变学测试和红外光谱显示,环氧树脂低聚物与基体树脂PA66和分散相TLCP分子在熔融加工过程中原位发生化学反应,环氧树脂低聚物在共混物界面起到桥的作用。     

PA6/POE共混物的分子动力学与介观动力学模拟

为了预测聚己内酰胺(PA6)与聚烯烃热塑性弹性体(POE)的相容性及其共混物的玻璃化转变温度(Tg)、力学性能和结合能,采用分子动力学(MD)和介观动力学(MesoDyn)模拟方法对PA6/POE共混物进行了研究。结果表明:通过温度-比容曲线可以得到PA6/POE共混体系的Tg分别对应于PA6与POE的Tg,PA6/POE为不相容体系;Meso-Dyn模拟了共混物的介观形貌与动力学演变过程,通过比较混合物的有序度参数的大小判断混合物为不相容体系。本模拟方法可以作为预测聚合物共混物性能的有利工具,也可以为高聚物配方设计提供理论指导。     

聚丙烯/聚烯烃弹性体/硅灰石复合材料的制备与热学力学性能

采用熔融共混的方法制备聚丙烯(PP)/聚烯烃弹性体(POE)/硅灰石(Wollastonite)复合材料,利用万能材料试验机、悬臂梁冲击机、差热扫描量热仪(DSC)和扫描电镜(SEM)研究了聚烯烃弹性体和硅灰石对聚丙烯的力学性能及热性能的影响。结果表明,POE弹性体对PP有很好的增韧作用,提高了PP的冲击强度,硅灰石在一定程度上有增强的作用,提高了PP/POE的拉伸强度;POE和硅灰石使复合材料的结晶温度有所提高,但使熔点有所降低。当POE占3%(质量分数,下同),硅灰石占3%时,复合材料的热学、力学性能最优,冲击强度比纯PP高出15.4%,拉伸强度高出2.6%,结晶温度高出5℃。     

原位交联改性PP/POE共混物的等温结晶行为

采用热塑性聚烯烃弹性体(POE)作为增韧材料,以过氧化二异丙苯(DCP)为交联剂制备了PP/POE共混物。利用差示扫描量热仪(DSC)和偏光显微镜(PLM)研究了PP/POE共混物等温结晶行为,并用Avrami方程分析了PP/POE共混物结晶动力学。结果表明,POE的加入能起到异相成核的作用,加快了PP的结晶成核速率。Avrami指数在1.93～3.09,DCP的引入对聚丙烯(PP)的成核与生长机理影响不大,但其原位交联作用阻碍了PP分子链的运动,使得PP结晶速率降低,结晶时间延长。     

PS/POE增容母料对SAN/PS/POE共混物结构及性能的影响

利用Friedel-Crafts烷基化反应制备了聚苯乙烯(PS)/聚烯烃弹性体(POE)(50/50,质量比,下同)增容共混物。抽提结果显示,该共混物中PS-g-POE接枝共聚物的质量分数为28.3%。以该共混物作为增容母料,考察其对苯乙烯-丙烯腈共聚物/聚苯乙烯/聚烯烃弹性体(SAN/PS/POE)共混体系力学性能、热稳定性、微观结构等方面的影响。结果表明,固定SAN/PS/POE共混物组成,部分PS、POE组分被增容母料取代后,共混物性能得到明显提高,共混物SAN/PS/POE(50/20/30)与SAN/母料/POE(50/40/10)相比,其拉伸强度从10.8 MPa上升至21.0 MPa,断裂伸长率从1.6%上升至22.3%;热重分析显示,增容共混物中易分解组分的热稳定性提高,共混物SAN/PS/POE(20/10/70)与SAN/母料/POE(20/20/60)相比,其易分解组分的分解温度从413.6℃提高到425.1℃;从扫描电镜(SEM)照片可以看出,增容共混物中分散相更均匀细小。     

PA66/PA6I6T共混物非等温结晶动力学及性能

将PA66与PA6I6T以不同配比进行熔融共混,通过差示扫描量热分析对所制备的尼龙66 (PA66)与半芳香尼龙(PA6I6T)共混物在不同降温速率下的非等温结晶行为进行了研究。利用Jeziorny法及Mo方法对共混物的非等温结晶动力学数据进行了分析,并采用Kissinger方法计算了共混体系的结晶活化能;考察了PA6I6T含量对共混物力学性能、耐热性及加工流动性的影响。研究发现,PA66与PA6I6T具有良好的相容性,少量的PA6I6T会促进PA66的结晶,随着PA6I6T含量的进一步增加,PA66的结晶速率及结晶度呈下降趋势,PA66的结晶活化能的绝对值随PA6I6T含量的增加表现为先增大后减小。共混物的拉伸强度和冲击强度随PA6I6T含量的增加而增加,其中拉伸强度在PA6I6T达到一定含量后趋于平缓。PA6I6T的引入提高了共混物的耐热性和热稳定性,但加工流动性较纯PA66材料有一定程度降低。     

Microstructural,thermal and rheological correlations to mechanical response of polyamide-6(glass filled)/polyetherimide blend: effect of ethylene-octene copolymer on toughening of blend

Melt mixed glass-filled polyamide 6(PA6)/polyetherimide (PEI) blends were prepared in a co-rotating twin screw extruder over the entire composition range of 0–100 wt% of polyamide 6. These blends were characterized by structural, rheological, mechanical and thermal properties. Crystallization behavior and phase morphology of the blends were also investigated. The blend with the composition PA6/PEI 75/25 showed overall improved mechanical properties along with low resultant viscosity which can be processed on standard equipment. Shear viscosity along with shear stress of the blends were analyzed using shear rheometer which concluded that the blends can be processed on standard equipment due to resultant low viscosity. Scanning electron microscope micrographs revealed that the morphology of the blends showed a two phase structure in which the minor phase was dispersed as domains in the continuous phase. Polyolefin elastomer (POE) as impact modifier was added to the above composition in the range of 0–15 phr to study its effect. The thermal characteristics of PA6, PEI, and PA6/PEI blends with and without POE were investigated using DSC and TGA which revealed that the melting temperature and crystallization temperature of the blend remained unchanged while XRD results showed percent crystallinity was increased slightly. Furthermore, it can be said that the blend with composition PA6/PEI 75/25 with 10 phr impact modifier loading was suitable for high end applications because it combines the high mechanical properties of glass-filled PA6 with inherent flame-retardant property of PEI while POE overcomes the physical weakness of moisture absorption.     

Superior toughness obtained via tuning the compatibility of poly(ethylene terephthalate)/poly(ethylene–octene) blends

As a partial of the systematic investigation of the preparation and characterization of poly(ethylene terephthalate) (PET) blending/compounding materials with excellent comprehensive mechanics in the authors’ group, this study deals with the compatibilization modification of PET/elastomer blends to obtain superior toughness. Poly(ethylene–octene) (POE) was employed as elastomer toughener, while maleic anhydride grafted POE (mPOE) was selected as compatibilizer. To highlight the effect of compatibility on toughening, the sum amount of elastomer component, POE and mPOE, was fixed at 20 wt%, but the mass ratio of mPOE/POE was changeable. It is interesting to find that an optimization of toughening can be attained at 3 wt% mPOE, at which the notched impact strength is about 15 folds for that of neat PET. The toughening behavior observed is due to a combination of good dispersion of elastomer phase particles and, particularly, appropriate interfacial adhesion condition. Microscopic fractured morphology reveals that a moderate level of interfacial adhesion is important for good dispersion of elastomer phase and debonding between PET matrix and elastomer particles, which initiate matrix shear yielding to dissipate more energy than other interfacial adhesion conditions.     

界面粘结对PET／尼龙66共混物结晶行为和力学性能的影响

利用ＳＥＭ、ＤＳＣ等方法，比较了尼龙６和尼龙６６对ＰＥＴ结晶的异相成核作用，研究了界面粘结状况对ＰＥＴ／尼龙６６共混物结晶行为及力学性能的影响。结果表明，尼龙６６对ＰＥＴ结晶的成核能力优于尼龙６。虽然界面粘结听改善不利于ＰＥＴ／尼龙６６共混物的结晶，但是经明显提高了共混物的力学性能。     

Effect of EVOH on the morphology,mechanical and barrier properties of PA6/POE-g-MAH/EVOH ternary blends

Polyamide 6 (PA6)/maleated poly(ethylene-1-octene) (POE-g-MAH) blends with various ethylene–vinyl alcohol (EVOH) concentrations were prepared via melt-blending. The morphology, mechanical and barrier properties of the blends were investigated in terms of scanning electron microscope (SEM), impact/tensile testing, dynamic mechanical analysis (DMA) and oil absorption rate. The SEM images indicated that the compatibility between PA6 and POE-g-MAH was improved significantly after the incorporation of EVOH. The toughness of blends was correlated with the morphology of the POE-g-MAH and EVOH dispersion phase. It has also demonstrated that the incorporation of EVOH increased evidently the tensile strength, storage modulus and barrier properties, which were contributed to the strong interactions formed through the reaction among PA 6, POE-g-MAH and EVOH.     

Morphologies and physical properties of PA1010/HIPS/HIPS-g-MA ternary blends

The effect of the content of a copolymer consisting of high impact polystyrene grafted with maleic anhydride (HIPS-g-MA) on morphological and mechanical properties of PA1010/HIPS blends has been studied. Blend morphologies were controlled by adding HIPS-g-MA during melt processing, thus the dispersion of the HIPS phase and interfacial adhesion between the domains and matrices in these blends were changed obviously. The weight fractions of HIPS-g-MA in the blends increased from 2.5 to 20, then much finer dispersions of discrete HIPS phase with average domain sizes decreased from 6.1 to 0.1 m were obtained. It was found that a compatibilizer, a graft copolymer of HIPS-g-MA and PA1010 was synthesized in situ during the melt mixing of the blends. The mechanical properties of compatibilized blends were obviously better than those of uncompatibilized PA1010/HIPS blends. These behaviors could be attributed to the chemical interactions between the two components of PA1010 and HIPS-g-MA and good dispersion in PA1010/HIPS/HIPS-g-MA blends. Evidence of reactions in the blends was seen in the morphology and mechanical behaviour of the solid. The blend containing 5 wt% HIPS-g-MA component exhibited outstanding toughness.     

PP/POE/滑石粉三元复合材料的研究

研究了弹性体(POE)、滑石粉、偶联剂和填料处理方式对聚丙烯(PP)的力学性能、加工性能、结晶行为以及无机粒子在基体中分散形态的影响。结果表明,PP 2(K 7726)/POE(80/20)二元共混体系的综合性能较好;采用方式C(将两种偶联剂按1∶1的质量比,先加钛酸酯后加硅烷处理滑石粉)制得的PP 2/POE/T a lc(80/20/25)三元复合材料的力学性能比其它两种方式有显著提高。偏光显微镜(PLM)研究表明,方式C处理的滑石粉在体系中分散性最好;扫描电镜(SEM)显示,三元复合体系由PP 2/POE耗能少的空洞化断裂方式向耗能多的剪切屈服方式转变;DSC表明,采用方式C处理的滑石粉对聚丙烯的成核作用减弱。     

PP对PBT/POE-g-MAH共混体系相形态和力学性能的影响

将聚丙烯(PP)与官能化聚烯烃弹性体(POE-g-M AH)共混,制备出4种新型增韧改性剂,研究了PP的含量和种类对PBT/POE-g-M AH共混体系相形态和力学性能的影响。SEM观察发现,新型增韧改性剂作为分散相具有以POE-g-M AH为软壳、PP为硬核的包藏结构。随着高熔体流动指数PP(EPF 30R)含量的增加,软壳层厚度逐渐减小,包藏结构分散相的相畴尺寸略有减小,分布更加均匀。但添加低熔体流动指数PP(EPS30R)后,包藏结构分散相的相畴尺寸变大,分布不均匀。力学性能测试表明,适量高熔体流动指数PP与POE-g-M AH并用具有显著的协同增韧作用。与PBT/POE-g-M AH体系相比,在相同的增韧剂总用量时,共混物在保持超高韧性的同时,拉伸强度损失最小。     

热空气老化对LDPE/POE共混物结晶行为和力学性能的影响

在70℃条件下,对低密度聚乙烯(LDPE)/聚烯烃弹性体(POE)共混物进行八周热空气老化试验,通过差示扫描量热法(DSC)和宽角X射线衍射(WAXD)表征了共混物结晶行为的变化,研究了热空气老化对共混物力学性能的影响。w(POE)为30%的共混物具有优异的耐热氧老化性能,在老化前期,其断裂伸长率有所增加,在老化后期才略有下降,而拉伸强度则基本不变。热空气老化对共混物结晶行为产生明显的影响,且结晶行为的变化主要在老化前期完成。经过热空气老化,部分在制备过程中形成的不完善晶体重新结晶,晶粒尺寸逐渐变大,提高了LDPE结晶的完善性。     

超韧尼龙11合金的力学性能和相态研究

研究了尼龙11和POE的共混物，制备了不同的马来酸酐接枝率的尼龙11／POE－g－MAH和尼龙11／POE／POE－g-MAH共混物，研究了共混物的力学性能和相态。结果表明，引入POE－g-MAH能够提高相容性和共混物的韧性，并且马来酸酐接枝率越高效果越为明显，与此同时，拉伸强度却降低得很少。