正电子湮没技术在橡塑共混体系中的应用

通过正电子湮没寿命谱技术(PALS)探测聚合物的自由体积特性,能够了解聚合物的微观性质。介绍了应用PALS在三元乙丙橡胶、丙烯酸酯类共聚物、丁苯橡胶与塑料共混体系中有关自由体积特性的研究现状。实验结果表明PALS作为一种微孔探针技术,能够在橡塑共混体系相容性研究方面发挥重要作用。     

聚丙烯微孔发泡材料制备及改性进展

聚丙烯(PP)微孔发泡材料具有质轻、力学性能较高的特点,PP基体性质、发泡剂种类、发泡制备成型工艺、化学改性方法、共混及填充改性等方法均可以影响发泡材料的泡孔结构及发泡材料的性能。综述了PP微孔发泡材料的制备成型工艺、化学、共混、纳米、填充等改性方法研究进展,指出采用成本低廉、无毒的化学类发泡剂制备泡孔结构良好的PP微孔发泡材料将是今后研究的热点。PP的交联及接枝改性技术,与其它聚合物、填料共混技术是改善泡孔结构、提高泡沫材料发泡性能和力学性能的途径,研究改性材料与PP基体材料的界面相容性问题也是今后的研究方向。     

聚合物共混物的形态结构与物性

本文主要对高分子材料的嵌段、接枝共聚物及聚合物共混物的形态结构与物性进行定性叙述。     

聚丙烯接枝共聚物增大聚丙烯共混体系相容性的研究

本文采用尼龙1010(1010)、无机碳酸钙及硅酸钙分别与聚丙烯(pp)及聚丙烯的马来酸酐接枝共聚物(pp-g-MAH),制备六类聚丙烯共混物。用偏光显微镜、相差显微镜、扫描电镜研究它们的形态、分散状态及相界面。观察到与 pp-g-MAH 的共混物中分散相粒子都比其它 pp 共混物中的小且分散均匀,而相界面均较模糊。结果表明 pp-g-MAH 能改善聚丙烯与尼龙1010、碳酸钙、硅酸钙等极性物质间的相容性。     

丁腈橡胶共混改性研究概况

丁腈橡胶（NBR）以其优异的耐热性、耐老化和耐磨性及优良的导电性在聚合物共混领域得到了大量的研究及应用。采用共混方法,将NBR和其它具有弹性、纤维性或塑性的聚合物共混,产生具有某些特殊性能的新材料。本文介绍了丁腈橡胶与其它橡胶、树脂及热塑性弹性体共混改性的研究概况。     

热塑性聚氨酯与弹性体的共混及应用

本文简要论述了热塑性聚氨酯和苯乙烯嵌段共聚物的结构与性能。在分析聚合物共混的基本条件如混溶性与相容性的基础上,介绍了热塑性聚氨酯与热塑性弹性体(如苯乙烯嵌段共聚物)的共混方法及设备,并对其共混效果与应用作了简单的介绍。     

共混增容的反应性聚合物

将不相容聚合物共混为开发具有有用的综合性能的新材料提供了诱人机会．然而，简单的共混物普遍存在机械性能不良和相结构不稳定的问题，故对这种共混物的增韧非常必要．传统方法是采用预先制备好的接校或嵌段共聚物作为增容剂．而另一种途径是采用官能化的共聚物在熔融共混体系中产生共聚物增容剂．本文考证了在聚合物共混物的反应性增容方面已应用的许多反应性聚合物．根据它们所含的反应性基团的种类，分成六大类即马来酸酐类、羧酸类、羧酸的衍生物类、伯胺和仲胺类、羟基环氧类，以及可产生离子键的反应性基团类．本文叙述它们的制备方法、应用以及在熔融共混过程中经历的化学反应。     

CPE三元接枝共聚物对CPE／AS共混物的改性研究

在高分子共混增容理论与高分子共混物多相体系流变学的指导下，利用合成的CPE与AN，St的三元接枝共聚物对CPE/AS共混体系进行改性。扫描电镜（SEM）测试结果表明三元接枝共聚物加入CPE/AS共混体系后能有效改善体系相容性。增容作用明显。流变性能测试表明，一定量的CPE三元接枝共聚物加入CPE/AS共混体系后，能有效降低体系的熔体粘度，克服了增容与共混熔体粘度增加的矛盾。制备出具有良好力学与加工性能的CPE/CPE三元接枝共聚物/AS共混材料。讨论了共混体系的增容机理与加工流动性改善的原因。研究表明，共混材料中CPE，AS，CPE三元接枝共聚物的含量分别为30，60，10（质量份）时，其综合性能优良。     

聚合物共混材料中氢键的研究进展

综述了近年来国内外聚合物共混材料中氢键的研究现状,着重对影响聚合物共混材料氢键强弱的因素、氢键的研究方法、氢键对聚合物共混材料性能的影响以及基于氢键作用制备相容性聚合物共混材料的方法进行总结。指出进一步研究多组分聚合物材料的氢键相互作用,可为制备可控性聚合物共混相容材料、实现功能化材料的构筑提供理论指导。     

聚烯烃共混体系反应性增容研究的进展

综述了近期国内外通过将能发生化学反应的聚合物进行熔融共混、加入能与共混组分起反应的聚合物、添加能与共混组分在熔融共混过程中形成共聚物或产生交联的低分子化合物 3种方法进行聚烯烃共混体系反应性增容研究的进展     

聚乳酸/尼龙11/氯醚弹性体三元共混体系结构与性能研究

以生物基尼龙11(PA11)和氯醚橡胶(ECO)作为聚乳酸(PLA)的增韧和耐热改性剂,通过熔融共混的方法制备了PLA/PA11/ECO三元共混体系,并系统表征了体系的相容性、形貌结构、热行为及物理性能.PA11的存在改善了共混体系组分之间相容性.连续相PA11能有效提高PLA基体的维卡软化温度至160 ℃以上.PLA...     

EPDM/聚烯烃共混型热塑性弹性体的研究

制备ＥＰＤＭ／聚烯烃简单共混型热塑性弹性体。研究了聚合物种类、橡塑比、二元和三元共混对共混物力学性能的影响。结果表明，部分结晶性ＥＰＤＭ共混物的力学性能比无定形ＥＰＤＭ共混物好，部分结晶性ＥＰＤＭ与ＬＤＰＥ（低密度聚乙烯）共混物的拉伸强度大于两者的加和值，而其它二元共混物的拉伸强度均低于两共混单元的加和值；用ＬＤＰＥ部分替代ＰＰ，或用氯磺化聚乙烯（ＣＳＭ）部分替代结晶性ＥＰＤＭ进行三元共混，能改善部分结晶性ＥＰＤＭ／ＰＰ共混物的某些性能。     

Thermoplastic natural rubber based on polyamide‐12: Influence of blending technique and type of rubber on temperature scanning stress relaxation and other related properties

Thermoplastic natural rubber based on polyamide‐12 (PA‐12) blend was prepared by melt blending technique. Influence of blending techniques (i.e., simple blend and dynamic vulcanization) and types of natural rubber (i.e., unmodified natural rubber (NR) and epoxidized natural rubber (ENR)) on properties of the blends were investigated. It was found that the simple blends with the proportion of rubber ～ 60 wt % exhibited cocontinuous phase structure while the dynamically cured blends showed dispersed morphology. Furthermore, the blend of ENR exhibited superior mechanical properties, stress relaxation behavior, and fine grain morphology than those of the blend of the unmodified NR. This is attributed to chemical interaction between oxirane groups in ENR molecules and polar functional groups in PA‐12 molecules which caused higher interfacial adhesion. It was also found that the dynamic vulcanization caused enhancement of strength and hardness properties. Temperature scanning stress relaxation measurement revealed improvement of stress relaxation properties and thermal resistance of the dynamically cured ENR/PA‐12 blend. This is attributed to synergistic effects of dynamic vulcanization of ENR and chemical reaction of the ENR and PA‐12 molecules. Furthermore, the dynamically cured ENR/PA‐12 blend exhibited smaller rubber particles dispersed in the PA‐12 matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Radiation crosslinking of poly(vinyl chloride)/epoxidized natural rubber blend: effect of lead stabilization of the poly(vinyl chloride) phase

The irradiation crosslinking of 50/50 poly(vinyl chloride)/epoxidized natural rubber blend was investigated in the presence of 1–5 parts per hundred resin (phr) tribasic lead sulfate (TBLS) with blends prepared at various mixing temperatures. The blends were irradiated using a 3.0 MeV electron accelerator at 0, 100 and 200 kGy irradiation doses. Changes in tensile strength, elongation at break and stress‐strain curves of the blends with the increase TBLS content and blending temperatures were observed before and after irradiation. The results on the tensile properties revealed the inhibition of the irradiation‐induced crosslinking by the TBLS although it stabilizes the blend against thermal and irradiation‐induced degradation. The Fourier transform infrared spectroscopy studies further confirmed these observations. Control on the thermal degradation of the blend during blending found to be crucial in achieving maximum enhancement in blend properties upon irradiation. Evidence from dynamic mechanical analysis was also used to support this contention. Addition of 2 phr TBLS and blending at 150 °C found to be adequate in order to achieve the best enhancement in blend properties through irradiation‐induced crosslinking. © 2001 Society of Chemical Industry     

Studies on polymer blends: Blending methods for natural rubber and styrene-butadiene rubber

The relations between the properties and the blend ratios of natural rubber (NR) and styrene-butadiene rubber (SBR) blends were studied in comparison with four blending methods. The relations between the properties of unvulcanized and vulcanized blends and the blend ratios of blends prepared by means of solution blending, latex blending, roll blending, and Banbury mixer blending were studied. In practice, such rubber blending methods as roll blending are more effective for obtaining uniform blends than Banbury mixer blending the latter. In roll blending, it is more effective to blend NR and SBR by way of a master-batch in which the ingredients are compounded beforehand than to blend raw rubber. In solution and latex blending, very uniform blends are easily obtained. It was found, however, that the properties of NR/SBR blends prepared carefully showed a direct relation to their blend ratios, regardless of blending method used.     

成型加工中PC/PS微观结构的生成和演化

用扫描电镜(SEM)研究了聚碳酸酯／聚苯乙烯共混物在3种工业级熔融混合加工过程中形态结构的生成和演化。结果表明，共混物双相共连续形态结构的生成和演化强烈地依赖于共混物的组成和混合方法，相转变点的理论预测与试验值有一定的偏差，混合初期体系会形成片状、层叠状和纤维状的形态结构。但由于流动场和界面力的影响，这种片、层状结构不稳定，而纤维状结构易于在高剪切力的情况下出现。     

Structure and physical properties of cellulose acetate/poly(butylene succinate) blends containing a transition metal alkoxide

Two biodegradable polymers, that is, poly(butylene succinate) (BN) and cellulose acetate (CA), were solvent‐cast blended with chloroform. Homogeneous films were obtained from the blend by the addition of tetraisopropyl titanate (TP) as a compatibilizer. We measured the viscosity of the blend solution to investigate the function of TP during the blending process. From the measurement, we conclude that there are interactions among TP, BN, and CA. From optical observation and thermal measurements of the blend films, we found that the structure of blends is in a pseudostable state and that the addition of TP makes the structure units small. From thermogravimetric analyses, we found that the addition of TP decreases the thermal decomposition temperature of the BN/CA blends. From the measurements of mechanical properties of the blends, we found that changing the blend ratio can produce the materials with a wide range of mechanical properties. The hydrolysis of the blends was investigated. The molecular scission of BN/CA blends takes place uniformly not only from the outside but also from the inside of the films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1750–1758, 2002     

聚苯乙烯—聚乙烯的反应性共混研究

用ＩＲ，ＤＳＣ，ＤＭＡ等分析方法了研究恶唑啉官能化聚苯乙烯（ＲＰＳ）与马来酸酐接枝聚乙烯（ＭＰＥ）的共混反应，对反应性共混物及相应的非反应性共混物作了应力－应变试验，发现反应性共混提高了ＰＥ／ＰＳ共混物的力学性能，改变了ＭＰＥ的结晶情况。     

Mechanical and morphological properties of lyocell blends: Comparison with lyocell nanocomposites (I)

The mechanical properties and morphologies of polyblends of lyocell with three different fillers are compared. Poly(vinyl alcohol) (PVA), poly(vinyl alcohol‐co‐ethylene) (EVOH), and poly(acrylic acid‐co‐maleic acid) (PAM) were used as fillers in blends with lyocell produced through solution blending. The variations of their properties with polymer matrix filler content are discussed. The ultimate tensile strength of the PVA/lyocell blend is highest for a blend lyocell content of 30 wt %, and decreases as the lyocell content is increased up to 40 wt %. The ultimate tensile strengths of the EVOH/lyocell and PAM/lyocell blends are highest for a lyocell loading of 20 wt %, and decrease with the increasing filler content. The variations in the initial moduli of the blends with filler content are similar. Of the three blend systems, the blends with PVA exhibit the best tensile properties. Lyocell/organoclay hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium–Mica (C₁₂PPh‐ Mica) as the organoclay. The variation of the mechanical tensile properties of the hybrids with the matrix polymer organoclay content was examined. These properties were found to be optimal for an organoclay content of up to 5 wt %. Even polymers with low organoclay contents exhibited better mechanical properties than pure lyocell. The addition of organoclay to lyocell to produce nanocomposite films was found to be less effective in improving its ultimate tensile strength than blending lyocell with the polymers. However, the initial moduli of the nanocomposites were found to be higher than those of the polyblend films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

偶联剂改性对磁敏NR/SBR并用胶性能的影响

将NR和SBR与改性羰基铁粉机械共混制备磁敏NR/SBR并用胶,研究偶联剂KH-550,KH-560,KH-570和NDZ-401改性羰基铁粉对磁敏NR/SBR并用胶的物理性能和磁流变效应的影响。结果表明:不同偶联剂改性的羰基铁粉对NR/SBR并用胶性能有一定的影响;采用偶联剂KH-570改性的羰基铁粉填充的NR/SBR并用胶表现出较好的物理性能和磁流变效应。