iPS—b—iPP共聚物对iPS／iPP共混物的性能和形态影响的研究

报道了苯乙烯－丙烯等规嵌段共聚物增溶作用及ｉＰＳ－ｂ－ｉＰＰ／ｉＰＳ／ｉＰＰ三组分共混体系微观形态和力学性能的研究结果。ｉＰＳ－ｂ－ｉＰＰ的加入明显地改善了ｉＰＳ／ｉＰＰ二组分共混物的力学性能；共聚物含量超过１５％时，三组分共混物的抗冲击强度超过ＨＩＰＳ的抗冲击强度，并具有较高的耐热性。ＳＥＭ结果表明，ｉＰＳ－ｂ－ｉＰＰ在ｉＰＳ／ｉＰＰ共混中起到了相分散和相间“偶联”作用，并降低了共混体系的微相尺     

聚二甲基硅氧烷／聚氨酯共混体系的增容作用（I）

采用二甲基硅氧烷－ｂ－乙二醇嵌段共聚物（ＤＭＳ－ｂ－ＯＥ）对聚二甲基硅氧烷／聚氨酯（ＰＤＭＳ／ＰＵ）共混体系的增容，重点研究了增容共混体系的微观形态结构和软科学性能之间的关系。扫描电子显微镜、动态力学分析和力学性能测试结果表明：ＤＭＳ－ｂ－ＯＥ对ＰＤＭＳ／ＰＵ具有优良的增容作用，改善了ＰＤＭＳ／ＰＵ共混体系的相容性，提高了该共混物的力学性能。其抗张强度由３．４ＭＰａ提高到７．６ＭＰａ。     

热致液晶／PEEK／嵌段共聚物共混体系的结构与性能

用ＷＡＸＤ、ＳＥＭ及力学性能测试等研究热致液晶／ＰＥＥＫ／嵌段共聚物三元共混体系形态、结构和性能。结果表明嵌段共聚物的加入，使体系具有一定的相容性和较好的界面粘接，共混物的强度、模量有一定的提高，对共混物的结晶行为具有明显的影响，当热致液晶含量高时，基材与液晶两相间出现明显的分离现象，即“皮－芯”结构．     

用SN型催化剂合成苯乙烯－丙烯嵌段共聚物的研究II．共聚物的结构表征与性能

报道用稀土化合物改性的钛系截体催化剂（ＳＮ催化剂）进行苯乙烯和丙烯顺序嵌段共聚合（Ｓｅｑｕｅｎｔｉａｌｂｌｏｃｋｃｏｐｏｌｙｍｅｒｉｚａｔｉｏｎ）的研究，通过对初生嵌段共聚产物进行溶剂萃取与分级，并用１３Ｃ－ＮＭＲ、ＷＡＸＤ．ＤＳＣ，ＤＭＡ和电子显微镜进行表征，推断共聚物为具有等规聚苯乙烯链和等规聚丙烯链段的Ａ－Ｂ型二嵌段共聚物，且各段均能结晶。发现嵌段共聚物比相应的均聚物具有较好的综合力学性能和热性能，而且对ｉＰＳ／ｉＰＰ共混具有良好的增容作用。     

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。     

POM／EVA共混物的研究

用力学测试、扫描电镜（ＳＥＭ）、热分析（ＤＳＣ）等手段研究了聚甲醛（ＰＯＭ）与乙烯－醋酸乙烯酯共聚物（ＥＶＡ）共混物（ＰＯＭ／ＥＶＡ）的力学性能及其微同形态；用聚甲醛与马来酸二丁酯（ＤＢＭ）的接枝物（ＰＯＭ－ｇ－ＤＢＭ）作相溶剂，能改变共的两相间的粘结力，从而提出了共混物的力学性能，ＳＥＭ观察表明接枝物的加入改变了ＰＯＭ／ＥＶＡ共混物的断裂方式，微观形态及结晶性能，对其热性能影响不大；通过改变ＰＯ     

聚酰胺1010／聚乙烯－马来酸酐接枝共聚物共混物力学和热学性能研究

为了表明马来酸酐接枝聚烯烃后对聚酰胺的相容作用，本文研究了聚酰胺１０１０（ＰＡ１０１０）／聚乙烯－马来酸酐接枝共聚物（ＰＥ－ｇ－ＭＡＨ）共混物在不同ＭＡＨ接枝量下的结晶性与力学性能。研究表明，ＭＡＨ的存在导致ＰＥ－ｇ－ＭＡＨ－ｃｏ－ＰＡ１０１０共聚物的形成，而该共聚物在标题共混物中起着相容剂的作用。共混物的结晶性能变化显示了共混组分间存在一定程度的混溶性。在一定的ＭＡＨ含量内，标题共混物具有协同效应。     

PVC/PBD-b-PMMA共混体系相容性的研究

采用ＤＭＡ和ＴＥＭ系统研究了聚丁二烯－聚甲基丙烯酸甲酯的嵌段共聚物（ＰＢＤ－ｂ－ＰＭＭＡ）与聚氯乙烯（ＰＶＣ）共混体系的相容性问题。结果表明：ＰＶＣ／ＰＢＤ－ｂ－ＰＭＭＡ共混体系具有部分相溶性。相容的程度与共混体系的组成、组分聚合物的分子量以及共聚物中ＰＢＤ和ＰＭＭＡ嵌段的比例密切相关。     

苯乙烯—丙烯嵌段共聚物等温结晶动力不宾研究

用ＤＳＣ法研究苯乙烯－丙烯嵌段共聚物（ｉＰＳ－ｂ－ｉＰＰ）的等温结晶动力学，结果表明，在所选择的结晶温度（１２７－１３２℃）范围内，共聚物很好地符合Ａｖｒａｍｉ动力学方程；共聚物结晶温度，结晶速率，结晶成和生长方式都与共聚物结构和组成比在关，随着嵌段共的中ｉＰＳ段含量的增加，结晶速率和Ａｖｒａｍｉ指数（ｎ）明显降低。     

离聚物Surlyn对PBT/PP共混体系的力学性能及形态结构的影响

用力学性能测试、ＤＭＡ、ＳＥＭ等方法研究了离聚物Ｓｕｒｌｙｎ对ＰＢＴ／ＰＰ共混体系的力学性能及形态结构的影响。结果表明，在ＰＢＴ／ＰＰ共混体系中引入少量Ｓｕｒｌｙｎ可以改善界面的粘接性，从而改善其力学性能。当共混体系中ＰＢＴ／ＰＰ的组份比不变（９０／１０）且Ｓｕｒｌｙｎ的含量为６ｐｈｒ左右时，共混物的冲击强度出现极大值；而弯曲强度在Ｓｕｒｌｙｎ含量为１－２ｐｈｒ左右时有最大值。当共混体系中Ｓｕｒｌｙｎ的含量不变（６ｐｈｒ）时，其力学性能随ＰＰ含量的增加而下降。用玻璃纤维增强共混体系，可显著提高力学性能。     

Phase morphology and mechanical properties of iPP/SEP blends

The effects of the addition of diblock copolymer poly(styrene‐b‐ethylene‐co‐propylene) (SEP) to isotactic polypropylene (iPP) on the morphology and mechanical properties were investigated. Phase morphologies of iPP/SEP blends up to a 70/30 weight ratio, prepared in Brabender Plasticoder, were studied with optical microscopy, scanning electron microscopy, transmission electron microscopy, and wide‐angle X‐ray diffraction. The addition of 2.5 wt % SEP caused a nucleation effect (by decreasing the crystallite and spherulite size) and randomization of the crystallites. With further SEP addition, the crystallite and spherulite size increased because of prolonged solidification and crystallization and achieved the maximum in the 80/20 iPP/SEP blend. This maximum was a result of the appearance of β spherulites and the presence of mixed α spherulites in the 80/20 iPP/SEP blend. Dispersed SEP particles were irregular and elongated clusters consisting of oval and spherical core–shell microdomains or SEP micelles. SEP clusters accommodated their shapes to interlamellar and interspherulitic regions, which enabled a well‐developed spherulitization even in the 70/30 iPP/SEP blend. The addition of SEP decreased the yield stress, elongation at yield, and Young's modulus but significantly improved the notched impact strength with respect to the strength of pure iPP at room temperature. Some theoretical models for the determination of Young's modulus of iPP/SEP blends were applied for a comparison with the experimental results. The experimental line was closest to the Takayanagi series model. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 566–580, 2001     

间规聚苯乙烯/等规聚丙烯/间规聚苯乙烯-b-聚(1-丁烯)共混体系相容性

间规聚苯乙烯(sPS)的改性主要是对其增韧改性,提高其力学性能.sPS的化学改性已有较多文献报道[1,2].     

Structure and mechanical properties of talc‐filled blends of polypropylene and styrenic block copolymers

The structure–property relationships of isotactic polypropylene (iPP)/styrenic block copolymer blends filled with talc were examined by optical and scanning electron microscopy, wide‐angle X‐ray diffraction, and tensile‐ and impact strength measurements. The composites were analyzed as a function of the poly(styrene‐b‐ethylene‐co‐propylene) diblock copolymer (SEP) and the poly(styrene‐b‐butadiene‐b‐styrene) triblock copolymer (SBS) content in the range from 0 to 20 vol % as elastomeric components and with 12 vol % of aminosilane surface‐treated talc as a filler. Talc crystals incorporated in the iPP matrix accommodated mostly plane‐parallel to the surface of the samples and strongly affected the crystallization process of the iPP matrix. The SBS block copolymer disoriented plane‐parallel talc crystals more significantly than the SEP block copolymer. The mechanical properties depended on the final phase morphology of the investigated iPP blends and composites and supermolecular structure of the iPP matrix because of the interactivity between their components. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1255–1264, 2004     

Synthesis of Isotactic Polystyrene-block-Polyethylene by the Combination of Sequential Monomer Addition and Hydrogenation of 1,4-Trans-polybutadiene Block

Herein, we demonstrate the synthesis of a well-defined diblock copolymer consisting of isotactic polystyrene(iPS) and linear polyethylene, isotactic polystyrene-block-polyethylene(iPS-b-PE),by the combination ofsequential monomer addition and hydrogenation. Isospecific living polymerization of styrene and living trans-1,4-polymerization of 1,3-butadienewere catalyzed by 1,4-dithiabutandiyl-2,2′-bis(6-cumenyl-4-methylphenoxy) titanium dichloride(complex 1) activated by triisobutyl aluminum modified methylaluminoxane(MMAO) at room temperature to provide highly isotactic polystyrene(iPS) and 1,4-trans-polybutadiene(1,4-trans-PBD) with narrow molecular weight distribution. Furthermore, the iPS-b-1,4-trans-PBD was synthesized via sequential monomer addition in the presence ofcomplex 1 and MMAO.The hydrogenation of the 1,4-trans-PBD block was promoted by RuCl_2(PPh_3)_3 used as a catalyst to produce iPS-b-PE.     

Crystallization,thermal behavior,and compatibility in isotactic polystyrene/poly(o-chlorostyrene-co-p-chlorostyrene) blends

The dependence of the kinetics of crystallization and melting behavior in isotactic polystyrene/poly-o-chlorostyrene-co-p-chlorostyrene (iPS/Po-CIS-co-p-CIS) blends on temperature, thermal history, and blend composition has been investigated. The crystallization rate at a given temperature and copolymer composition decreases with increasing copolymer content in the blend when the samples are premelted. These effects can be ascribed to the reduction of mobility of the crystallizable chains due to the presence of the copolymer and to the decrease in the number of heterogenous iPS nuclei as a result of the premelting process. The Avrami exponent values and the analysis of the blend morphology indicate that the growth mechanism of the crystals is strongly influenced by thermal treatment. There is no measurable change in the melting temperature of iPS in the blends, with composition indicating that, on the basis of the Flory-Huggins approximation of the thermodynamics of polymer mixing, the net interaction parameter at the melting temperature is close to zero. From the comparison of the phase diagram for the isotactic polystyrene-containing blend with that of the atactic-containing blend, it can be concluded that in the amorphous state polystyrene with a regular configuration is slightly less compatible with the P(o-CIS-co-p-CIS) than is polystyrene with random configuration.     

Dynamic mechanical investigations on drawn samples of isotactic polypropylene/EPM–Rubber blend

The physical behavior of isotropic and oriented samples of an isotactic polypropylene (iPP)/ethylene–propylene–copolymer (EPM) reactor blend was studied by performance of dynamic mechanical measurements over a wide temperature range (DMTA). The influence of thermal history and drawing procedure was examined. The results showed that with increasing draw ratio the uniaxial elastic modulus of the material was considerably enhanced, whereas the intensity and strength of the amorphous relaxations of both components were reduced. At a certain draw ratio, the glass transtions of iPP and EPM phenomenologically merged and appeared as a single relaxation. The crystalline relaxation of iPP emerged with increased draw ratio at higher temperatures and was better seperated and easier to detect. The effects observed were attributed to the orientation of the crystallites in a fibrillar structure and to the restricted molecular mobility in amorphous regions. Measurements by differential scanning calorimetry (DSC) and x-ray diffraction of several drawn samples were performed to determine the effects of drawing on the melting behavior and the crystal orientation in the semicrystalline polymer. For comparison, some results of analogous studies on neat isotactic PP are presented and discussed. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 1439–1448, 1997     

Surface segregation of polypeptide-based block copolymer micelles: An approach to engineer nanostructured and stimuli responsive surfaces

We describe the surface segregation of polypeptide-based block copolymer micelles to produce stimuli-responsive nanostructures at the polymer blend/air interface. Such structures were obtained by simultaneous surface migration and self assembly at the surface of diblock copolymer/homopolymer blends. We employed blends composed of homopolymer (PS) and an amphiphilic block copolymer polystyrene-b-poly(l-glutamic acid) (PS-b-PGA). The surface was functionalized based on the preferential segregation to the polymer blend/air interface of the hydrophilic PGA block of the diblock copolymer upon annealing to water vapor. The surface migration of the diblock copolymer to the interface was demonstrated both by XPS and contact angle measurements. As a consequence, the PGA interfacial attraction leads to a large surface excess on diblock copolymer which in turn, through macrophase and microphase separation, produced separated domains at the surface with regions composed either of homo or block copolymer. Herein we demonstrate that the use of asymmetric diblock copolymers with a higher content in PS lead to spherical micellar assemblies randomly distributed at the surface. As observed by AFM imaging the blend composition, i.e. the amount of block copolymer within the blend influences the density of micelles at the surface. Finally, when exposed to water, the pH affects the surface morphology. The PGA segments are collapsed at low pH values and extended at pH values above 4.8, thus inducing variations on the topography of the films at the nanometer scale.     

Simultaneously reinforce and toughen polypropylene by in‐situ introducing polylactic acid microfibrils

A petroleum‐based polymer, isotactic polypropylene (iPP), and a biodegradable polymer, poly(lactic acid) (PLA), were compounded and molded into parts through the micro‐injection technique. A systematic structural investigation indicated that the microfibrillation of PLA minor phase depended on the operation parameter of inter‐mixer, ie, rotor speed. The higher rotor speed, the lower viscosity ratio of the PLA/iPP pair was favorable for microfibrillation occurred during micro‐injection process. The PLA microfibrils with high aspect ratio was successfully introduced into iPP matrix, and the tensile strength and strain at break of iPP/PLA blends were simultaneously improved. This study suggests a promising method for designing special microfibrillar morphology in polymer blend by using conventional melt processing techniques.     

Heterogeneous nucleation of crystallization of high polymers from the melt. I. Substrate-induced morphologies

Melt crystallization of isotactic polypropylene (iPP), poly(ethylene oxide), poly(butene-1), and polycaprolactone in contact with various substrates (mostly polymeric) has been studied by hot stage polarizing microscopy. Nucleating abilities of surfaces have been characterized qualitatively by examining the substrate-induced morphologies of the crystallizing polymer. These morphologies have been classified into three groups, depending on whether the substrate is very active (transcrystallinity), moderately active, or inactive as a nucleating agent. The morphologies observed are temperature-dependent, changing from transcrystalline to spherulitic upon increase of the crystallization temperature. At intermediate temperatures, mixed surface morphologies (transcrystalline plus spherulitic) are observed. The concentration of titanium and aluminum catalytic residues in isotactic polystyrene (iPS) samples can be reduced by two methods, i.e., (a) fractionating the polymer and (b) chelating Ti and Al with acetylacetone. The high nucleating ability of iPS samples in the crystallization of iPP has been shown to be due to the polymer (iPS) itself, and not to Ti and Al residues. Apart from iPS, other polymers (low energy surfaces) have also been found to induce transcrystallinity. From a survey of 43 substrate-crystallizing polymer pairs, conclusions have been drawn which are relevant to the following potential factors in heterogeneous nucleation processes: (a) chemical structure, (b) crystallographic unit cell type, (c) lattice parameters, (d) crystallinity of substrate, and (e) surface energy of substrate.     

Monte Carlo simulation on symmetric ABA/AB copolymer blends in confined thin films

The effects of blend composition on morphology, order-disorder transition (ODT), and chain conformation of symmetric ABA/AB copolymer blends confined between two neutral hard walls have been investigated by lattice Monte Carlo simulation. Only lamellar structure is observed in all the simulation morphologies under thermodynamic equilibrium state, which is supported by theoretical prediction. When the composition of AB diblock copolymer (phi) increases, both lamellar spacing and the corresponding ODT temperature increase, which can be attributed to the variation of conformation distribution of the diblock and the triblock copolymer chains. In addition, both diblock and triblock copolymer, chains with bridge conformation extend dramatically in the direction parallel to the surface when the system is in ordered state. Finally, the copolymer chain conformation depends strongly on both the blend composition and the incompatibility parameter chiN.