PP/PA11合金的结晶性能研究

用马来酸酐接枝聚丙烯(PP-g-MA)和苯乙烯-马来酸酐无规共聚物(RSMA)作增容剂,制备了PP/PA11合金,并对合金的结晶性能进行了研究。傅立叶转换红外光谱(FTIR)表明,RSMA的增容机理与PP-g-MA不同。比较了2种增容体系的差示扫描量热(DSC)曲线,发现PP-g-MA增容体系中PP的熔融温度向更高温度移动,同时PP-g-MA的加入更能影响PP和PA11两相的结晶,使体系的结晶度增大,从而使合金的缺口冲击性能表现出更强的脆性。     

Impact modification of polypropylene by ethylene propylene copolymer‐grafted maleic anhydride

Blends of polypropylene (PP) and ethylene propylene rubber (EPR) were studied. The effect of the level of rubber addition and the ethylene content is described. The results show that the viscosity of the PP, rubber content, ethylene content, and grafted EPR by maleic anhydride (MA) are important factors in controlling the blend properties. The miscibility and dynamic properties of the blends were studied by DMTA. Impact and tensile properties were also studied. SEM was used for the investigation of the phase morphology and rubber particle size and particle‐size distribution. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1257–1265, 1999     

尼龙66和马来酸酐LDPE接枝共聚物的力学性能

将马来酸酐和LDPE进行接枝反应后得到的共聚物，和尼龙66共混，由于LDPE－g-MAH上的酸酐基团与尼龙66上的胺基相互作用，它们有很好的相容性，随着LDPE－g-MAH加入量的增加，尼龙66的冲击韧性有很大提高。     

尼龙／乙烯—醋酸乙烯酯共聚物接枝马来酸酐共混体系的研究

通过双螺杆挤出机利用熔融挤出法制备了增韧的尼龙66／乙烯－醋酸乙烯酯共聚物接枝马来酸酐共混物（PA66／EV－g-MAH）。实验结果表明，未经接枝改性的EVA与PA66是不相容的，对增韧PA66几乎没有贡献，而EVA－g-MAH则出现了明显的增韧效果。在熔融挤出过程中，PA66与EVA－g-MAH发生了原位化学反应，生成了PA66－EVA共聚物，这种共聚物细化了分散相尺寸，使得分散相在PA66基体中分散得更均匀，提高了两相的相容性，同时增强了丙相界面间的结合力，便利应力能够在两相产有效地传递，这种界面形态的改善直接影响到共混物力学性能的变化。随着EVA－g-MAH含量的增加，PA66/EVA-g-MAH共混物的冲击强度提高，当PA66／EVA－g-MAH的共混比为70／30（质量比）进，体系发生了脆韧转变，冲击强度达到了最大，比纯PA66、PA66／EVA（70／30）共混物提高了12倍。和PE－g-MAH、PP-g-MAH相比，EVA-g-MAH对PA66的增韧效果最好。     

聚酰胺—聚烯烃共混体系的研究进展

对聚酰胺-聚烯烃共混体系的改性方法,增容机理、相态结构、热行为及力学性能等方面进行了综合评述,展望了共混体系的应用及开发前景。     

The Use of Ethylene/Propylene Copolymers as Compatibilizers for Recycled Polyolefin Blends

Compatibilizing effects of ethylene/propylene (EPR) diblock copolymers on the morphology and mechanical properties of immiscible blends produced from recycled low‐density polyethylene (PE‐LD) and high‐density polyethylene (PE‐HD) with 20 wt.‐% of recycled poly(propylene) (PP) were investigated. Two different EPR block copolymers which differ in ethylene monomer unit content were applied to act as interfacial agents. The morphology of the studied blends was observed by scanning‐ (SEM) and transmission electron microscopy (TEM). It was found that both EPR copolymers were efficient in reducing the size of the dispersed phase and improving adhesion between PE and PP phases. Addition of 10 wt.‐% of EPR caused the formation of the interfacial layer surrounding dispersed PP particles with the occurrence of PE‐LD lamellae interpenetration into the layer. Tensile properties (elongation at yield, yield stress, elongation at break, Young's modulus) and notched impact strength were measured as a function of blend composition and chemical structure of EPR. It was found that the EPR with a higher content of ethylene monomer units was a more efficient compatibilizer, especially for the modification of PE‐LD/PP 80/20 blend. Notched impact strength and ductility were greatly improved due to the morphological changes and increased interfacial adhesion as a result of the EPR localization between the phases. No significant improvements of mechanical properties for recycled PE‐HD/PP 80/20 blend were observed by the addition of selected block copolymers.     

组分对PA6/PP/滑石粉三元复合材料的影响

通过双螺杆挤出制备了尼龙6(PA6)/聚丙烯(PP)/滑石粉三元复合材料,考察不同PA6、PP及滑石粉和增容剂种类及含量对PA6/PP/滑石粉三元复合材料力学性能的影响。结果表明,中黏度(2.4~2.7 Pa·s)PA6、聚乙烯(PE)含量达到7%~9%的嵌段共聚PP及粒径为2~5μm的滑石粉制备的PA/PP/滑石粉三元复合材料具有优异的力学性能;随着PA6含量增加,PA6/PP/滑石粉三元复合材料的拉伸、弯曲强度增加,吸水率上升,PP含量增加,PA6/PP/滑石粉三元复合材料吸水率下降,拉伸强度和弯曲强度也下降;滑石粉的粒径越大,PA6/PP/滑石粉三元复合材料的刚性越好,冲击强度越差,滑石粉的粒径越小,则容易团聚,三元复合材料形成应力集中点;增容剂马来酸酐接枝乙烯-醋酸乙烯酯共聚物(EVAC-g-MAH)和马来酸酐接枝三元乙丙橡胶(EPDM-g-MAH)复配对PA6/PP/滑石粉三元复合材料增容效果优于马来酸酐接枝聚丙烯(PP-g-MAH)或EPDM-g-MAH;当EVAC-gMAH和EPDM-g-MAH添加量各为5%,PA6/PP/滑石粉质量比为50/20/20时,制备出的PA6/PP/滑石粉三元复合材料具有较佳的力学性能,并有优异的加工性能,其缺口冲击强度可达6.6 k J/m^2。     

相容剂对PP/PA6复合材料力学性能的影响

研究了2种相容荆PP—g-MAH（马来酸酐接枝聚丙烯）、POE—g—MAH（马来酸酐接枝乙烯辛烯共聚物）对PP／PA6（聚丙烯／聚酰胺6）共混体系力学性能的影响。研究结果表明，2种相容荆的加入都使PP／PA6体系的相容性增加，但PP—g—MAH的加入主要表现为增强效果，而POE-g-MAH的加入主要表现为增韧效果。     

Improved thermal stability and mechanical properties of poly(propylene carbonate) by reactive blending with maleic anhydride

To extend the application of a carbon dioxide sourced environmental friendly polymer: poly (propylene carbonate) (PPC), a small amount of maleic anhydride (MA) was melt blended to end‐cap with PPC to improve its thermal stability and mechanical properties. Thermal and mechanical properties of end‐capped PPC were investigated by TGA, GPC, mechanical test, and DMA. TGA and titration results demonstrate that PPC can be easily end‐capped with MA through simple melt blending. TGA results show that the thermal degradation temperature of PPC could be improved by around 140°C by adding MA. GPC measurement indicates that the molecular weight of PPC can be maintained after blending with MA, where pure PPC experiences a dramatic degradation in molecular weight during melt process. More importantly, the tensile strength of PPC after blending with MA was found to be nearly eight times higher than that of pure PPC. It has approached the mechanical properties of polyolefin polymers, indicating the possibility of replacing polyolefin polymers with PPC for low temperature applications. The method described here could be used to extend the applications of PPC and fight against the well known global warming problem. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Blends of bisphenol A polycarbonate and rubber‐toughened styrene–maleic anhydride copolymers

The morphology and mechanical properties of polycarbonate (PC) blends with rubber‐toughened styrene–maleic anhydride copolymer materials (TSMA) were investigated and compared with the properties of blends of PC with acrylonitrile–butadiene–styrene (ABS) materials. The PC/TSMA blends showed similar composition dependence of properties as the comparable PC/ABS blends. Polycarbonate blends with TSMA exhibited higher notched Izod impact toughness than pure PC under sharp‐notched conditions but the improvements are somewhat less than observed for similar blends with ABS. Since PC is known for its impact toughness except under sharp‐notched conditions, this represents a significant advantage of the rubber‐modified blends. PC blends with styrene–maleic anhydride copolymer (SMA) were compared to those with a styrene–acrylonitrile copolymer (SAN). The trends in blend morphology and mechanical properties were found to be qualitatively similar for the two types of copolymers. PC/SMA blends are nearly transparent or slightly pearlescent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1508–1515, 1999     

Molecular and Morphological Characterization of Immiscible SAN/EPDM Blends Filled by Nano Filler

The compatibilizing effect of nano sized calcium carbonate filler on immiscible blends of styrene‐co‐acrylonitrile/ethylene propylene diene (SAN/EPDM) was examined. The surface energy of the calcium carbonate was modified by stearic acid. The compatibility of SAN/EPDM blends was studied by following the glass transition temperature T_g by DSC. SEM was used to observe the blend morphology and the X‐ray analyzer was used to detect the calcium from filler in samples. Mechanical properties of the blends were determined, and related to changes of polymer‐filler interactions and morphology. The results suggest that the morphology of the SAN/EPDM blends studied was affected by the reduction of surface energy of the filler.

SEM micrograph of an SAN/EPDM blend with 5% of maximally treated filler.     

Environmental Stress‐Cracking Resistance of LDPE/EVA Blends

Blends of low‐density polyethylene with random copolymers of ethylene and vinyl acetate (PE/EVA) are studied with respect to their environmental stress‐cracking resistance (ESCR) using the Bell‐telephone test. This system shows the shortest time to failure in the ESCR test after annealing at 50 °C in a stress‐cracking agent (Igepal solution) compared with that in the tests conducted at 30 and 70 °C. The increase of the time to failure at 70 °C as compared with that at 50 °C is probably the result of the semicrystalline proportion of EVA melting. Transmission electron microscopy images (see Figure) reveal that EVA particles are molten and deformed in bending direction of the sample at 70 °C in contrast to samples annealed at 50 and 30 °C. TEM pictures of a failed sample during the test conducted at 50 °C indicate that EVA particles can stop crack propagation.

TEM image of PE/EVA‐5.4 after 1 000 h in ESCR test conditions at 70 °C.     

NBR/EPDM共混胶的增容研究

研究了增容剂二元乙丙橡胶接枝马来酸酐(EPM-g-MAH)和丁腈橡胶/甲基丙烯酸缩水甘油酯的共聚物(NBR-GMA)对NBR/EPDM共混胶力学性能和相形态结构的影响。结果表明,加入EPM-gMAH/NBR-GMA并用物后共混胶凝胶含量明显增大。随着增容剂用量的增大,共混胶相形态结构得到明显改善,力学性能有所提高,且共混胶的耐热性能好于耐油性能。共混胶DMA曲线表明,增容剂对NBR/EPDM共混胶有较好增容作用。     

离聚物surlyn对PET/PA66共混物性能的影响

摘要：采用傅里叶红外光谱、示差扫描量热法（DSC）考察了离聚物surlyn对PET/PA66共混体系结构、结晶性能的影响;通过低剪切速率下流变性能测试、力学性能测试以及热变形温度测试,考察了离聚物对该体系流变性能、力学性能、耐热性能的影响。实验结果表明：加入离聚物Surlyn增加了界面的粘接力和分子间的链缠结,使共混体系的相容性得到了提高,其中以离聚物Surlyn含量在10%效果较好。     

Comparison of propylene/ethylene copolymers prepared with different catalysts

This study compared a series of experimental propylene/ethylene copolymers synthesized by a transition metal‐based, postmetallocene catalyst (xP/E) with homogeneous propylene/ethylene copolymers synthesized by conventional metallocene catalysts (mP/E). The properties varied from thermoplastic to elastomeric over the broad composition range examined. Copolymers with up to 30 mol % ethylene were characterized by thermal analysis, density, atomic force microscopy, and stress–strain behavior. The xP/Es exhibited noticeably lower crystallinity than mP/Es for the same comonomer content. Correspondingly, an xP/E exhibited a lower melting point, lower glass transition temperature, lower modulus, and lower yield stress than an mP/E of the same comonomer content. The difference was magnified as the comonomer content increased. Homogeneous mP/Es exhibited space‐filling spherulites with sharp boundaries and uniform lamellar texture. Increasing comonomer content served to decrease spherulite size until spherulitic entities were no longer discernable. In contrast, axialites, rather than spherulites, described the irregular morphological entities observed in xP/Es. The lamellar texture was heterogeneous in terms of lamellar density and organization. At higher comonomer content, embryonic axialites were dispersed among individual randomly arrayed lamellae. These features were characteristic of a copolymer with heterogeneous chain composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1651–1658, 2006     

Thermal Behavior of Isotactic Poly(propylene)/Maleated Poly(propylene) Blends

This paper analyzes the thermal and thermo‐oxidative degradation behavior, phase separation, melting, and crystallization of blends consisting of isotactic poly(propylene) (IPP) and poly(propylene) grafted with maleic anhydride (PP‐g‐MA). It has been established that, depending on the blend composition and crystallization/preparation procedure, the blends of IPP and PP‐g‐MA can either co‐crystallize or evidence phase separation. This conclusion has been attained by comparing the DSC results of crystallization under dynamic and isothermal conditions with X‐ray diffraction results. On the basis of the obtained results, the optimum mixing ratios have been established as 95–85 wt.‐% IPP/5–15 wt.‐% PP‐g‐MA. Thermo‐oxidative behavior has been studied by thermogravimetry and differential thermal analysis.

     

PE-LLD/SEBS-g-MAH/POE-g-MAH共混体系流变性能的研究

在双螺杆挤出机中用马来酸酐（MAH）分别对乙烯-辛烯共聚物（POE）、氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）进行熔融接枝,用密炼机对线形低密度聚乙烯（PE-LLD）、POE-g-MAH和SEBS-g-MAH进行熔融共混,用毛细管流变仪对PE-LLD/SEBS-g-MAH二元体系和PE-LLD/POE-g-MAH/SEBS-g-MAH三元体系的流变行为进行研究。结果表明,LLDPE/POE-g-MAH/SEBS-g-MAH共混体系是典型的假塑性流体;体系的表观黏度随着SEBS-g-MAH组分含量的增加而增加,POE-g-MAH对共混体系表观黏度的影响较小。     

Mechanical property and morphology comparison between the two blends poly(propylene)/ethylene‐propylene‐diene monomer elastomer and poly(propylene)/maleic anhydride‐g‐ethylene‐propylene‐diene monomer

The comparison of the mechanical properties between poly(propylene)/ethylene‐propylene‐diene monomer elastomer (PP/EPDM) and poly(propylene)/maleic anhydride‐g‐ethylene‐propylene‐diene monomer [PP/MEPDM (MAH‐g‐EPDM)] showed that the latter blend has noticeably higher Izod impact strength but lower Young's modulus than the former one. Phase morphology of the two blends was examined by dynamic mechanical thermal analysis, indicating that the miscibility of PP/MEPDM was inferior to PP/EPDM. The poor miscibility of PP/MEPDM degrades the nucleation effectiveness of the elastomer on PP. The observations of the impact fracture mode of the two blends and the dispersion state of the elastomers, determined by scanning electron microscopy, showed that PP/EPDM fractured in a brittle mode, whereas PP/MEPDM in a ductile one, and that a finer dispersion of MEPDM was found in the blend PP/MEPDM. These observations indicate that the difference in the dispersion state of elastomer between PP/EPDM and PP/MEPDM results in different fracture modes, and thereby affects the toughness of the two blends. The finer dispersion of MEPDM in the blend of PP/MEPDM was attributed to the part cross‐linking of MEPDM resulting from the grafting reaction of EPDM with maleic anhydride (MAH) in the presence of dicumyl peroxide (DCP). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2486–2491, 2002     

Compatibilizing Effect of SEBS for Electrical Properties of LDPE/PS Blends

Summary: In the previous study, we observed compatibilizing effects of low density polyethylene (LDPE)/polystyrene (PS) with polystyrene‐block‐poly(ethylene‐co‐butylene)‐block‐polystyrene (SEBS), a triblock copolymer. Blends consisting of 70 wt.‐% LDPE and 30 wt.‐% PS were prepared with a SEBS concentration of up to 10 wt.‐%. This study examined the electrical properties such as the electrical breakdown, water tree length, permittivity and tan δ in the blends. The possibility of using these blends as insulating material substitutes for LDPE was investigated. The electrical breakdown strength reached a maximum of 66.67 kV/mm, which is superior to 50.27 kV/mm of the LDPE used as electrical insulators for cables. In addition, the water tree length decreased with increasing SEBS concentration. The water tree lengths of the blends containing SEBS were shorter than that of the LDPE. The permittivity of the blends was 2.28–2.48 F/m, and decreased with increasing SEBS concentration with the exception of S‐0. Tan δ of the blends increased smoothly with increasing SEBS content.

Breakdown strength , water tree length, permittivity and tan δ of the LDPE/PS/SEBS blends and raw materials.     

聚乙烯接枝马来酸酐／聚氯乙烯共混体系的研究

研究聚乙烯与马来酸酐单体接枝反应，探讨反应条件对接枝率的影响，通过红外光谱对接枝率结构进行表征；研究接枝物及聚氯乙烯含量对共混体系拉伸强度的影响规律，用扫描电子显微镜观察共混物中的界面形态。结果表明，低密度聚乙烯接枝马来酸酐／聚氯乙烯共混体系的相容性和力学性能均有较大提高，接枝率为10％左右，PVC含量为40%时，共混物的拉伸强度可达13．80MPa。