马来酸酐接枝热塑性弹性体在PP/PA6共混物中的作用

研究了马来酸酐接枝热塑性弹性体 (TPEg )作为增容剂对聚丙烯 (PP) 尼龙 6 (PA6 )共混体系的相容性、相态以及物理力学性能的影响 .研究结果表明TPEg的加入大大改善了PP PA6共混体系的相容性 ,且随TPEg含量的增大分散相粒径明显降低 ,共混物的韧性以及延展性大大提高 ,同时拉伸强度及模量仍保持较好的水平 .TPEg增容的PP PA6共混物的非等温结晶行为的研究表明 ,共混物中PP和PA6的结晶行为不同于各自纯的聚合物 ,PA6作为成核剂使PP的结晶温度提高 ;而PA6由于TPEg的加入 ,出现分级结晶现象 ,一级结晶温度略低于纯PA6的结晶温度 ,且随TPEg含量增大结晶受阻 ,二级结晶温度与PP的接近 .由于PP、PA 6以及TPEg之间存在较强的相互作用 ,三元共混物中PP及PA6的玻璃化转变温度分别较其纯聚合物升高 .基于上述结果 ,提出了本共混体系的结构模型     

POE-g-PMAH反应性增容PA1010/PP共混物的性能研究

乙烯-辛烯共聚物-g-聚马来酸酐(POE-g-PMAH)作为反应性增容剂,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、傅立叶变换红外光谱(FTIR)和示差扫描量热(DSC)测试,研究了POE-g-PMAH对PA1010/PP共混物的增容作用.结果表明,POE-g-PMAH的加入可以减小共混物的相区尺寸,当PA1010/PP/POE-g-PMAH=70/30/15时,分散相尺寸小而均匀;FTIR结果表明接枝在POE上的马来酸酐基团和PA1010在熔融共混期间发生了化学反应;DSC研究结果表明共混体系中PA1010和PP的结晶温度和结晶度随POE-g-PMAH的加入而降低,表明POE-g-PMAH的增容作用对PA1010和PP的结晶有抑制作用.力学性能测试结果表明随着POE-g-PMAH的增加,共混物的冲击强度逐渐增加,当POE-g-PMAH含量增加到15%时,干态冲击强度达到21.13 kJ/m2,是不加增容剂的3.1倍,而拉伸和弯曲强度可以保持较高水平.POE-g-PMAH的增容机理在于其支链中的马来酸酐能与PA1010中的胺基(NH2—)发生化学反应,而主链POE与PP有较好的亲和性,从而降低界面张力,减少相区尺寸,大幅度提高力学性能.     

PTW对PA1010/PP共混物的增容作用

为了增加聚酰胺1010/聚丙烯(PA1010/PP)共混物的相容性,提高共混物的力学性能,采用一种新型的反应型增容剂乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物(PTW)进行增容,通过扫描电镜(SEM)、力学性能、傅里叶变换红外光谱(FTIR)和差示扫描量热(DSC)测试,研究了PTW对PA1010/PP共混物的增容作用.结果表明,随着PTW的加入,共混物的相区尺寸明显变小,当PA1010/PP/PTW质量比为70∶30∶7时,分散相尺寸细小而均匀,表明PTW有较好的增容作用.FTIR结果表明,PTW上的环氧基团和PA1010在熔融共混中发生了化学反应.DSC研究结果表明,PA1010的结晶温度随PTW的加入而降低,说明PTW对PA1010结晶有抑制作用.另外,PTW的加入使PP的结晶温度下降,当PTW质量分数为5%时出现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说明,在PA1010基体中分散相PP尺寸非常细小.当PTW质量分数为7%时共混物的力学性能最佳,干态冲击强度达到13.93kJ/m2,是未加增容剂时的2倍,拉伸和弯曲性能基本不变.PTW的增容机理在于其分子链中的甲基丙烯酸缩水甘油酯能与PA1010发生化学反应,而乙烯链段与PP有较好的亲和性,从而降低界面张力,减少相区尺寸,大幅度提高力学性能.     

PP/POE共混物的P-V-T属性及压力对结晶温度的影响

采用PVT膨胀仪研究了PP/POE共混物的P-V-T属性, 利用Tait方程预测其比容和热膨胀系数(α), 研究了压力对结晶温度(Tc)的影响. 结果表明, Tait状态方程可用来预测部分相容的、半结晶PP/POE共混物的PVT行为. PP结晶前后的比容变化比POE的大得多, 随着POE含量的增加, PP/POE共混物结晶前后比容的变化均逐渐减小. PP在熔融状态下的α比固体状态的大, 而POE正好相反. PP/POE共混物的α随温度和压力的变化与其组成密切相关. 随着压力的增高, PP, POE及其PP/POE共混物的结晶温度均呈线性增高的趋势.     

环氧化三元乙丙橡胶增韧聚对苯二甲酸丁二酯的脆韧转变

环氧化的三元乙丙橡胶(eEPDM)与聚对苯二甲酸丁二酯(PBT)共混可以使PBT共混体的缺口冲击强度获得很大的提高.当eEPDM橡胶浓度为24wt%时,PBTeEPDM共混体的缺口冲击强度是纯PBT的12倍.随着eEPDM含量的增加,在室温下PBTeEPDM共混体出现了明显的脆韧转变,其脆韧转变的临界粒子间距为0.49μm.橡胶的加入及含量的增加使PBT体系的脆韧转变温度(TBD)向低温移动,且PBTuEPDM与PBTeEPDM共混体脆韧转变温度的差随橡胶含量的增加而逐渐增大.扫描电镜照片表明,在橡胶组成相同的情况下,PBT基体中分散的eEPDM粒子明显小于未环氧化的EPDM粒子.且eEPDM橡胶的粒子间距(ID)也明显地低于uEPDM橡胶粒子的ID,这导致PBTeEPDM共混体系在室温下出现脆韧转变.     

壳核结构增韧剂对热塑性共聚酯/聚乙烯辛烯弹性体共混体系增容与增韧的影响

研究了马来酸酐接枝的聚乙烯辛烯弹性体 /半结晶性塑料共混物 (TPEg)对热塑性共聚聚酯(PETG) /聚乙烯辛烯弹性体 (TPE)共混体系增容增韧作用的影响 .马来酸酐接枝物显著地改善了PETG与TPE之间的相容性 ,导致TPE分散相颗粒细化 ,并促使分散相颗粒面间距等于甚至小于实现脆韧转变所需的临界面间距 .在固定PETG基体含量为 85wt %的前提下 ,当TPEg在 15 %分散相中的含量由 2 0 %增加到30 %时 ,即TPEg在共混体系中的含量由 3 %增加到 4 5 %时 ,共混体系出现了由脆性到韧性的转变 ,冲击强度急剧升高     

反应性单体改性PP/PS共混物结晶与熔融行为

制备了三种反应性单体和两种PP接枝物改性的PP／PS共混物,用DSC研究了改性PP／PS共混物的结晶与熔融行为。结果表明：PS的加入提高了PP的结晶温度,两种接枝物的加入进一步提高共混物中PP的结晶温度,少量反应性单体对结晶温度影响不大,但高用量时则明显提高共混物的结晶温度;外加接枝物或者反应性单体对共混物中PP的熔融温度影响不大,但是熔融峰形与结晶温度高低有关。     

SEP对PP/PS共混物的增容作用

研究了苯乙烯 -乙烯 /丙烯二嵌段共聚物 (SEP)对聚丙烯 /聚苯乙烯 (PP/PS)共混物的形态和力学性能的影响。结果表明 ,SEP在PP/PS共混物中作为增容剂 ,降低了分散相的聚结 ,减小了分散相的平均粒子尺寸 ,大大改变了共混物的形态 ,提高了共混物的力学性能 ,对PP/PS( 2 0 /80 )共混物的增容作用较为显著     

PP—g—（GMA—co—St）对PA6—PC共混合的反应增容作用

用红外、扫描电镜、熔体流动速率和力学性能等测试方法,研究了甲基丙烯酸缩水甘油酯（GMA）和苯乙烯（St）多单体熔融接枝聚丙烯PP－g-(GMA-co-St)对PA6－PC共混合的反应增容作用。研究结果表明,在熔融共混过程中,PP－g-(GMA-co-St)中的环氧基与PA6的端氨基及PC的端羟基原位生成的接枝共聚物就有效地降低了共混物相间的界面张力,明显提高了共混物相界面的粘着力。少量的PP－g-(GMA-co-St)就能使PA6和PC的相容性得到显著改善。当PP－g-(GMA-co-St)的质量分数为10％时,共混物分散相的相区尺寸细化到0．2μm,其力学性能也有较大提高。PA6／PC／PP－g-(GMA-co-St)共混物的力学性能均衡,达到了弹性体增韧体系难以达到的效果。即使PP－g-(GMA-co-St)组分含量为20％时,共混物仍能保持较好的力学性能,特别是在共混物地韧性得以提高的同时,其强度和伸长率也提高。     

PBT/POE-g-MAH/PP共混体系的相态结构与性能

采用马来酸酐接枝乙烯-辛烯共聚物弹性体(POE-g-MAH)与聚丙烯(PP)在双螺杆挤出机上进行熔融共混,制备了3种新型增韧改性剂.研究了增韧改性剂的种类及其用量对共混物的力学性能、相形态结构、熔融与结晶行为的影响.力学性能测试表明,POE-g-MAH与适量PP并用具有显著的协同增韧作用,当POE-g-MAH与PP的配比为70/30时,所得增韧改性剂(POEg2)具有最佳的增韧效果.当POEg2含量达到15%时,共混物的缺口冲击强度(Is)从纯PBT的7.5 kJ/m2提高到51.2 kJ/m2,与15%的纯POE-g-MAH弹性体增韧PBT具有相近的缺口冲击强度值.同时,共混物的拉伸强度(σb)损失最小.采用AFM和SEM观察发现,新型增韧改性剂作为分散相具有软壳-硬核结构.DSC测试表明,随增韧改性剂中PP含量增加到一定值时,壳-核结构中软壳层出现不完整现象,导致界面作用力减小,共混物的Is和σb都出现明显下降.     

BRITTLE-DUCTILE TRANSITION OF PP/EPDM/ELASTOMERIC NANO-PARTICLE TERNARY BLENDS

The brittle-ductile transition is a very important phenomenon for polymer toughening. Polypropylene （PP） is often toughened by using rubbers, e.g., ethylene-propylene diene monomer （EPDM） has often been used as a modifier. In this article, the toughening of PP by using a new kind of rubber, known as elastomeric nano-particle （ENP）, and the brittleductile transition of PP/EPDM/ENP was studied. Compared to PP/EPDM binary blends, the brittle-ductile transition of PP/EPDM/ENP ternary blends occurred at lower EPDM contents. SEM experiment was carried out to investigate the etched and impact-fractured surfaces. ENP alone had no effect on the impact strength of PP, however, with the same EPDM content, PP/EPDM/ENP ternary blends had smaller particle size, better dispersion and smaller interparticle distance in contrary to PP/EPDM binary blends, which promoted the brittle-ductile transition to occur earlier.     

EFFECTS OF INTERPARTICLE DISTANCE, TEMPERATURE AND INTERFACIAL ADHESION ON BRITTLE-DUCTILE TRANSITION FOR NYLON 6/ABS BLENDS

The toughness of blends composed of nylon 6 and acrylonitrile-butadiene-styrene(ABS) compatibilized by using styrene-maleic anhydride(SMA) as a compatibilizer was measured over a wide temperature region.Results reveal that the combining effects of particle size and volume fraction of ABS on the toughness of nylon 6/ABS/SMA blends can be described through plotting brittle-ductile transition of the impact strength versus the interparticle distance(ID) on the assumption that ABS domains relieve the triaxial...     

Effect of nucleating agent on the brittle–ductile transition behavior of polypropylene/ethylene–octene copolymer blends

In the present work, α‐form nucleating agent 1,3:2,4‐bis (3,4‐dimethylbenzylidene) sorbitol (DMDBS, Millad 3988) is introduced into the blends of polypropylene/ethylene–octene copolymer (PP/POE) blends to study the effect of the nucleating agent on the toughness of PP/POE blends through affecting the crystallization behavior of PP matrix. Compared with the PP/POE blends, in which the toughness of the blends increases gradually with the increasing content of POE and only a weak transition in toughness is observed, addition of 0.2 wt % DMDBS induces not only the definitely brittle‐ductile transition at low POE content but also the enhancement of toughness and tensile strength of the blends simultaneously. Study on the morphologies of impact‐fractured surfaces suggests that the addition of a few amounts of DMDBS increases the degree of plastic deformation of sample during the fracture process. WAXD results suggest that POE induces the formation of the β‐form crystalline of PP; however, DMDBS prevents the formation of it. SEM results show that the addition of DMDBS does not affect the dispersion and phase morphologies of POE particles in PP matrix. DSC and POM results show that, although POE acts as a nucleating agent for PP crystallization and which enhances the crystallization temperature of PP and decreases the spherulites size of PP slightly, DMDBS induces the enhancement of the crystallization temperature of PP and the decrease of spherulites size of PP more greatly. It is concluded that the definitely brittle–ductile transition behavior during the impact process and the great improvement of toughness of the blends are attributed to the sharp decrease of PP spherulites size and their homogeneous distribution obtained by the addition of nucleating agent. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 577–588, 2008     

Preparation and properties of PP/PC/POE blends

In order to develop PP (polypropylene)‐based blends with balanced toughness and rigidity, the poly‐blends of PP/PC (polycarbonate)/POE (ethylene–octene copolymer) were prepared by applying styrene–ethylene–propylene–styrene (SEPS) as the macromolecular compatibilizer. The compatibilizing effect was studied in terms of the mechanical, morphologies and thermal properties, and the compatibilized PP‐based blends presented remarkable improvement in impact toughness and balanced tensile strength due to the formed special morphology structure. Additionally, by preparing the pre‐blend of PC/SEPS, the melt viscosity of the PP matrix can match that of the dispersed phase PC and POE, which led to a further improvement in the mechanical property of the blends. Copyright © 2009 John Wiley & Sons, Ltd.     

双路易斯酸催化原位增容乙烯辛烯共聚物/苯乙烯共混物的研究

采用新型双路易斯酸, 三甲基氯硅烷和三氯化铟,为催化剂引发傅氏烷基化反应,实现了乙烯辛烯共聚物（POE）和聚苯乙烯（PS）共混物的原位增容。红外光谱验证了接枝物的存在。用扫描电镜观察了反应共混体系和简单物理共混物的形态, 前者分散相的尺寸小于1 μm, 后者分散相的尺寸则较大, 一般为3～4 μm。原位生成的接枝物起到相容剂的作用,增容后的样品的力学性能得到较明显的提升。如：当POE /PS 为40/60 (wt%) 时, 与相同组成的物理共混的POE/PS 相比, 其悬臂梁冲击强度由1.9 kJ/m2 增加到9.7 kJ/m2, 断裂伸长率由3.4%提高到46.3%。增容后共混物的流变性能与物理共混物相比也发生了显著的变化。     

Ductile–brittle‐transition phenomenon in polypropylene/ethylene‐propylene‐diene rubber blends obtained by dynamic packing injection molding: A new understanding of the rubber‐toughening mechanism

For a more complete understanding of the toughening mechanism of polypropylene (PP)/ethylene‐propylene‐diene rubber (EPDM) blends, dynamic packing injection molding was used to control the phase morphology and rubber particle orientation in the matrix. The relative impact strength of the blends increased at low EPDM contents, and then a definite ductile–brittle (D–B) transition was observed when the EPDM content reached 25 wt %, at which point blends should fail in the ductile mode with conventional molding. Wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to investigate the shear‐induced crystal structure, morphology, orientation, and phase separation of the blends. WAXD results showed that the observed D–B transition took place mainly for a constant crystal structure (α form). Also, no remarkable changes in the crystallinity and melting point of PP were observed by DSC. The highly oriented and elongated rubber particles were seen via SEM at high EPDM contents. Our results suggest that Wu's criterion is no longer valid when dispersed rubber particles are elongated and oriented. The possible fracture mechanism is discussed on the basis of the stress concentration in a filler‐dispersed matrix. It can be concluded that not only the interparticle distance but also the stress fields around individual particles play an important role in polymer toughening. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2086–2097, 2002     

Dynamic Mechanical Behavior and Prediction for PP/POE Blends

Polypropylene(PP)/ethylene-octene copolymer(POE) blends were prepared with a twin-screw extruder.Their dynamic mechanical behavior were systematically investigated.The results show that PP/POE blends are heterogeneities with a partial compatible two-phase structure,the glass transition temperature of PP phases in the blends tends to shift towards high temperature with increasing the POE content,and the glass transition temperature of POE phases shifts towards the low temperature with increasing the PP conte...     

聚丙烯/POE共混组成对材料断裂行为的影响

采用基本断裂功(EWF)方法对聚丙烯(PP)/聚烯烃弹性体(POE)共混物的注射双边缺口拉伸试样的断裂行为进行了研究,比较了不同POE含量对共混物各断裂参数的影响.结果表明,PP和用量为5phr POE的共混物都可完全满足EWF方法的要求,共混物的断裂韧性-比基本断裂功we,较PP有显著提高;POE用量为10phr以上的共混物则出现明显的成颈现象而限制了EWF方法的应用;PP和各种POE用量的共混物都得到了其屈服所需要的比基本断裂功we,y和比塑性功β′wp,y.