茂金属乙烯/苯乙烯共聚物的开发

综述了近１０年来国内外在茂金属催化剂合成乙烯／本乙烯共聚物方面的研究状况,着重介绍了用限定几何形催化剂开发的ＥＳ共聚物的结构及物理机械性能。     

茂金属乙烯／苯乙烯增韧PP—R的力学性能与相态结构

首次研究了增韧PP－R／ES124（茂金属乙烯／苯乙烯）共混合金的力学性能。结果发现，20份的ES124可以实现PP－R的超韧化，其Izod冲击性能可高达838．33J／m，共混合金的冲击性能随ESI24 添加量的增大而提高，然而其拉伸性能却并没有大幅度降低。此外，共混合金的断裂伸长度弛得到了较好的改善，弹性模量的下降幅度较小。通过对共混合金冲击断面的亚微观相态分析，发现PP－R／ESI24共混体系的增韧机理，从断裂过程的发展历程来看，具有不同于以往韧性断裂形态的新现象，其机理符合本学科点提出的“多重裂延”超韧机理。     

新开发的茂金属PP无规共聚物

ABS树脂是由丙烯腈、丁二烯、苯乙烯共聚而成,它是工程树脂中比较便宜、易于加工的一种树脂。     

乙烯—醋酸乙烯酸共聚物对茂金属聚乙烯的改性研究

以添加不同比例的茂金属聚乙烯（mLLDPE）/乙烯-醋酸乙烯酯（EVA）共混物为研究对象，考察了EVA含量对mLLDPE/EVA共混物的力学性能，热性能，流变性能，动态力学性能和形态结构的影响，研究结果表明，EVA添加到mLLDPE中，增加了mLLDPE的剪切敏感度，降低了mLLDPE的熔融粘度，改善了mLLDPE的流动性和加工性，在一定的添加比例范围内mLLDPE和EVA具有很好的相容性，可以在改善mLLDPE加工性能，引入极性基团的同时又保持与纯mLLDPE相近的力学性能，但会导致共混物材料的刚性下降，柔性增加，热分析数据说明，mLLDPE/EVA共混体系中，在EVA含量较小时共混物存在大量共晶，与mLLDPE有很好的相容性，无论是熔融曲线还是降温曲线都只出现一个峰，当EVA含量增大时，mLLDPE/EVA共混物出现相分离，曲线出现双峰，但两峰值呈现靠近趋势，预示mLLDPE/EVA共混物中仍存在少量共结晶。     

乙烯-醋酸乙烯酯共聚物对茂金属聚乙烯的改性研究

以添加不同比例的茂金属聚乙烯 (mLLDPE) /乙烯 醋酸乙烯酯 (EVA)共混物为研究对象 ,考察了EVA含量对mLLDPE/EVA共混物的力学性能、热性能、流变性能、动态力学性能和形态结构的影响。研究结果表明 ,EVA添加到mLLDPE中 ,增加了mLLDPE的剪切敏感度、降低了mLLDPE的熔融粘度、改善了mLLDPE的流动性和加工性 ;在一定的添加比例范围内mLLDPE和EVA具有很好的相容性 ,可以在改善mLLDPE加工性能、引入极性基团的同时又保持与纯mLLDPE相近的力学性能 ,但会导致共混物材料的刚性下降 ,柔性增加。热分析数据说明 ,mLLDPE/EVA共混体系中 ,在EVA含量较小时共混物存在大量共晶 ,与mLLDPE有很好的相容性 ,无论是熔融曲线还是降温曲线都只出现一个峰。当EVA含量增大时 ,mLLDPE/EVA共混物出现相分离 ,曲线出现双峰 ,但两峰值呈现靠近趋势 ,预示mLLDPE/EVA共混物中仍存在少量共结晶     

聚氨酯/苯乙烯-马来酸酐无规共聚物反应性共混

采用反应性共混法合成聚氨酯／苯乙烯－马来酸酐无规共聚物共混物,用红外光谱,扫描电子显微镜研究了共混物的形态结构,并对共混物的性能进行了研究。     

茂金属乙烯－辛烯共聚物弹性体的应用

综述了茂金属乙烯－辛烯共聚物作为弹性体系材料的最新应用进展,采用藏属催化剂合成的乙烯－辛烯共聚物是一咎新型热塑性弹性体,可用注射,挤出,吹塑等常用加工方法成型,又可用过氧化物进行化学交联,用橡胶加工方法制成弹性体材料。     

橡胶增韧无规苯乙烯-马来酸酐共聚物

根据本院自制无规苯乙烯－马来酸酐共聚物（SMA）热分析结果，建立了共聚物中马来酸酐（MA）含量与玻璃化温度Tg的关系。测定了进口橡胶增韧SMA中橡胶和SMA基体的Tg值，测算了MA含量，比较了不同橡胶品种的Tg值，讨论了橡胶增韧SMA的机理、影响因素和应用前景。橡胶增韧SMA是一种具有高的耐热性、良好相容性和抗冲击性材料。     

苯乙烯-马来酸酐无规共聚物的研究进展

介绍苯乙烯(St)-马来酸酐(MAH)无规共聚物(R-SMA)的发展历程和聚合机理,分析R-SMA合成的影响因素,总结近年来R-SMA的主要聚合方法,并对R-SMA的未来发展进行展望。MAH与St极易进行交替聚合,可以通过提高温度和加入极性溶剂抑制交替聚合倾向,以合成R-SMA。溶液聚合法R-SMA具有传热效率高、可控性好的优点。在极性溶剂选择上,选择一种或多种混合环保型溶剂代替传统有机溶剂是需要解决的问题。     

茂金属乙烯-辛烯共聚物用作树脂改性剂的进展

概述了茂金属乙烯－辛烯共聚物在聚丙烯,聚乙烯,聚酯,聚酰胺,苯乙烯基树脂等中的应用进展。     

Mechanical behaviors of ethylene/styrene interpolymer compatibilized polystyrene/polyethylene blends

In this study, ethylene/styrene interpolymer was used as a compatibilizer for the blends of polystyrene (PS) and high‐density polyethylene (HDPE). The mechanical properties including tensile and impact properties and morphology of the blends were investigated by means of uniaxial tension, instrumented falling‐weight impact measurements, and scanning electron microscopy. Tensile tests showed that the yield strength of the PS/HDPE/ESI blends decreases considerably with increasing HDPE content. However, the elongation at break of the blends tended to increase significantly with increasing HDPE content. The excellent tensile ductility of the HDPE‐rich blends resulted from shield yielding of the matrix. Izod and Charpy impact measurements indicated that the impact strength of the blends increases slowly with HDPE content up to 40 wt %; thereafter, it increases sharply with increasing HDPE content. The impact energy of the HDPE‐rich blends exceeded that of pure HDPE, implying that the HDPE polymer can be further toughened by the incorporation of brittle PS minor phase in the presence of ESI compatibilizer. The correlation between the impact property and morphology of the blends is discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4001–4007, 2007     

Investigation of the interpolymer association between poly(vinyl alcohol) and poly(sodium styrene sulfonate) in aqueous solution

A viscosimetric method has been used to study the interpolymer association between poly(vinyl alcohol) (PVA) and poly(sodium styrene sulfonate) (PSSNa) in aqueous solution. At constant molecular weight of PSSNa, it was found that, the PVA and PSSNa associations were improved with the decrease of molecular weight of PVA and the decrease of its hydrolysis degree. The measurement of intrinsic viscosity [η] and the determination of Huggins associative coefficient K_H of different PVA samples were used to select the most appropriate PVA sample, which leads to homogeneous polymer–polymer mixtures (PVA with hydrolysis degree 87–89%, molecular weight 124,000–186,000 g/mol, intrinsic viscosity [η] = 1.02 dL/g, and Huggins associative coefficient K_h.ass = 0.76). The obtained results show that the interpolymer association between PVA and PSSNa, in aqueous solution, is mainly due to intermolecular hydrogen bonds between hydroxyl groups of PVA and sulfonate groups of PSSNa. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

pH and salt effects on interpolymer complexation via hydrogen bonding in aqueous solutions

The effect of inorganic salts addition on the complex formation of poly(acrylic acid) with various non‐ionic polymers such as poly(vinyl pyrrolidone), poly(acrylamide), poly(ethylene oxide), pol(vinyl methyl ether), poly(vinyl alcohol), poly(N‐isopropylacrylamide), poly(2‐hydroxyethyl vinyl ether), hydroxypropylcellulose and hydroxyethylcellulose has been studied in aqueous solutions. It was found that, depending on the nature of the polymers and pH medium, addition of inorganic salts could increase or decrease the critical pH values of complexation. A new classification of interpolymer complexes based on critical pH values and ionic strength effects is suggested. Copyright © 2004 Society of Chemical Industry     

Formation of interpolymer complexes between poly(monoethyl itaconate) and poly(N-vinyl-2-pyrrolidone)

This paper reports on the interpolymer complex formation and polymer blends between poly(monoethyl itaconate) (PMEI) and poly(N-vinyl-2-pyrrolidone) (PVP). The formation of the interpolymer complex was found to depend upon the solvent medium. Stoichiometry of the complexes prepared from methanol solutions, as calculated from elemental analysis, is close to 1 : 1. Specific interactions of PMEI/PVP complexes and blends of these polymers have been characterized by FTIR. Strong hydrogen bonding for complexes and blends has been found. A calorimetric study of the complexes and blends has been performed over a wide temperature range.     

Morphological and thermal characterization of interpolymer complexes and blends based on poly(acrylic acid) and hydroxypropylcellulose

Interpolymer complexes and blends were prepared based on poly(acrylic acid) and hydroxypropylcellulose. The structural features of polycomplexes and blends were evaluated by scanning electron microscopy and thermal analysis. It was found that the interpolymer complex obtained as a result of co‐precipitation of the polymeric components is characterized by an uniform structure which indicates the complete miscibility between the components. Films were prepared based on blends of neutralized poly(acrylic acid) and hydroxypropylcellulose. In this case the two components resulted immiscible because of the lack of intermolecular hydrogen bonding. Copyright © 2004 Society of Chemical Industry     

The phase behavior and thermal stability of blends of poly(styrene‐co‐methacrylic acid)/poly(styrene‐co‐ 4‐vinylpyridine)

The hydrogen bonding and miscibility behaviors of poly(styrene‐co‐methacrylic acid) (PSMA20) containing 20% of methacrylic acid with copolymers of poly(styrene‐co‐4‐vinylpyridine) (PS4VP) containing 5, 15, 30, 40, and 50%, respectively, of 4‐vinylpyridine were investigated by differential scanning calorimetry, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). It was shown that all the blends have a single glass transition over the entire composition range. The obtained T_gs of PSMA20/PS4VP blends containing an excess amount of PS4VP, above 15% of 4VP in the copolymer, were found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are able to form interpolymer complexes. The FTIR study reveals presence of intermolecular hydrogen‐bonding interaction between vinylpyridine nitrogen atom and the hydroxyl of MMA group and intensifies when the amount of 4VP is increased in PS4VP copolymers. A new band characterizing these interactions at 1724 cm⁻¹ was observed. In addition, the quantitative FTIR study carried out for PSMA20/PS4VP blends was also performed for the methacrylic acid and 4‐vinylpyridine functional groups. The TGA study confirmed that the thermal stability of these blends was clearly improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Investigation of thermoplastic elastomer (TPE) foaming process using blowing agent by rheological and morphological methods

The effects of a chemical blowing agent (CBA) or an encapsulated physical blowing agent (PBA) on morphological development in ethylene octene copolymer (EOC) matrix using dicumyl peroxide (DCP) as a curing agent were investigated by rheological, mechanical, and morphological methods. Temperature ramp tests were carried out to understand curing and foaming processes. Curing temperature (T_cure) was determined as the crossover temperature where storage modulus G′ coincided with loss modulus G′′ in the rheological point of view. For the CBA, T_cure increased with increasing CBA concentration, whereas for the PBA, T_cure decreased with increasing PBA concentration. Other critical temperatures T_1st, T_2nd by foaming process were determined using the axial normal force. With these critical temperatures (T_cure, T_1st, T_2nd), curing and foaming mechanisms can be estimated. Simultaneously, volume expansions of samples were observed with camera. Morphology and mechanical analysis were conducted on fully cured and foamed ECP (is defined as EOC with DCP) with blowing agent. ECP with the CBA exhibited an irregular open-cell structure, whereas when produced using the PBA, it formed a regular closed-cell structure. Specific tensile strength tended to increase with increasing PBA concentration but as blowing agent concentration increased elongation at break decreased. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47358.     

聚氨酯泡沫塑料工业氯氟烃发泡剂替代技术进展

叙述了聚氨酯泡沫塑料行业中发泡剂替代工作进展状况,分别介绍了国际上硬质泡沫和软质泡沫生产中的主要替代技术。     

Extrusion Foaming of Poly (lactic acid)/Soy Protein Concentrate Blends

Poly(lactic acid) (PLA) and soy protein concentrate (SPC) were compounded using poly(2‐ethyl‐2‐oxazoline) as compatibilizer by twin‐screw extrusion, and the resulting blends were foamed by a chemical blowing agent (CBA) using the same extruder. Effects of foaming temperature and CBA content on cell density and foam density were investigated. Polymeric methylene diphenyl diisocyanate (pMDI) as a co‐compatibilizer was added prior to foaming extrusion and its effects on foam morphology and properties were also studied. The results showed that cell density and foam density were greatly influenced by foaming temperature and CBA content. Using the strong interfacial modifier pMDI in PLA/SPC blends resulted in high‐cell density and low‐foam density when CBA concentration was low.

     

发泡剂ADC母料在EVA发泡制品中的应用

将自制的发泡剂保,偶氮二甲酰胺(ADC)母料,应用于乙烯-乙酸乙酯共聚物(EVA)发泡材料中,并与ADC粉料对比。结果表明:ADC母料配合的EVA发泡材料的拉伸强度、撕裂强度及弹性,均好于ADC粉料配合的EVA发泡材料。扫描电镜发现,ADC粉料配合的EVA发泡材料中存在较大泡孔,且存在串孔结构;而ADC母料配合的EVA发泡材料泡孔细密均匀且为闭孔结构。说明ADC母料化有利于制取泡孔细密均匀且为闭孔结构、强度高、弹性好的发泡材料。