成核剂对聚乳酸结晶改善的研究进展

聚乳酸作为一种有良好应用前景的绿色生物材料,结晶速率缓慢制约着聚乳酸更广泛的应用。添加成核剂是改善高聚物结晶性能的有效手段。文章综述了不同种类聚乳酸成核剂近年来的研究进展,对各类成核剂的特点和成核机理进行总结,并展望了今后聚乳酸成核剂的研究方向。     

有机磷酸盐类成核剂对PP性能的影响

研究了4种有机磷酸盐类成核剂对聚丙烯性能的影响。结果表明，这几种有机磷酸盐类成核剂可以有效地改善聚丙烯性能，制得高强度、高耐热透明聚丙烯。合成的有机磷酸盐类成核剂应用效果良好。     

聚丙烯β成核剂的研究进展

综述了近年来聚丙烯β成核剂的研究现状及进展,重点介绍了4种有机类β成核剂的成核效率和优缺点。稠环类β成核剂成核效率较低,生产成本高,产品易着色,目前很少应用;第ⅡA族金属元素的某些盐类及二元羧酸的复合物类β成核剂成核效率高,但生产成本较高、耐热性差;芳香酰胺类β成核剂成核效率高、热稳定性好,但价格较高;稀土类β成核剂成核效率高,可使聚丙烯韧性得到大幅增强,负荷变形温度也明显提高。     

中国塑料专利

正专利名称:无机填料改性剂和改性无机填料及其制备方法和应用以及聚丙烯复合材料及其制备方法申请公布号:CN108059770A申请公布日:2018.05.22本发明涉及聚合材料领域,具体提供了一种无机填料改性剂,该改性剂包括:界面增容剂和β成核剂,其中,β成核剂与界面增容剂的质量比为0.04:1~2:1。本发明提供了一种改性无机填料及其制备方法和应用,该方法包括:将无机填料、界面增容剂和β成核剂混合     

稀土β聚丙烯成核剂研究及应用进展

综述了稀土单核及多核β晶型成核剂的制备方法、组成,全面评述了以La为代表的稀土成核剂在均聚PP、各种共聚PP及再生PP中的应用,介绍了稀土成核剂与α成核剂、稀土成核剂与稀土偶联剂复合应用的进展。对不同种类的PP,稀土成核剂具有很高的β晶型成核能力,成核PP具有热变形温度高、冲击强度大、耐热稳定性好等优点。指出应重点加强稀土成核剂结构、成核机理及与其它助剂复合规律的研究。     

辐照交联聚丙烯成核剂

辐照交联聚丙烯是一种新型成核剂。本文介绍了该成核剂在聚丙烯双向拉伸薄膜中的应用,并对制品的结晶度和成核剂用量的关系、结晶温度和时间、微观结构、力学性能及透明度作了效果评定。     

聚丙烯酰胺类β成核剂研究进展

目前应用的聚丙烯主要为α聚丙烯和β聚丙烯。α聚丙烯存在材料冲击性能差、耐热性差等局限,而β聚丙烯可以显著地改善这一问题。β成核剂改性是目前生产β聚丙烯的主要办法。酰胺类β成核剂是一类高效β成核剂,具有热稳定性好、成核效果优秀、可以大幅提升聚丙烯力学性能的特点。文章主要综述了聚丙烯β成核剂的研究进展,分析了聚丙烯β成核剂的成核机理以及成核性能影响因素,最后对β成核剂的未来发展做出了展望和建议。     

浅析成核剂在聚丙烯中的作用

添加成核剂是一种有效的聚丙烯改性方法。聚丙烯成核剂可使聚丙烯结晶度增加、结晶细微化,提高其机械性能等。本文通过介绍聚丙烯成核剂的种类,特性,浅析了成核剂在聚丙烯中作用及其发展。     

聚乳酸生物质成核剂研究进展

成核剂在改善聚乳酸（PLA）结晶性能中具有重要作用,本文介绍了PLA的结晶行为,综述了PLA用生物质成核剂的国内外研究进展,包括多糖类成核剂淀粉、纤维素、甲壳素、壳聚糖和环糊精,酚类成核剂木质素,醇类成核剂肌醇,蛋白质类成核剂氨基酸以及羧酸类成核剂乳清酸;其次,提出了目前生物质成核剂应用中存在的问题与改性方法;最后,展望了PLA生物质成核剂未来发展前景。     

有机磷酸盐类成核剂对PP性能的影响

研究了4种有机磷酸盐类成核剂对聚丙烯性能的影响。结果表明，这几种有机磷酸盐类成核剂可以有效地改善聚丙烯性能，制得高强度、高耐热透明聚丙烯．合成的有机磷酸盐类成核剂应用效果良好。     

塑料制品的添加剂—成核剂的分类及研究

成核剂是促进聚合物结晶并改善其晶粒结构的改性剂，它主要包括无机类成核剂、有机类成核剂和高分子类成核剂，在聚合物中加入成核剂，加成了结晶速度，使聚合物的晶粒结构细化，缩短了成形周期，改善了产品的物理机械性能，使产品具有良好的加工和使用性能。     

A novel highly efficient β‐nucleating agent for polypropylene using nano‐CaCO3 as a support

In order to increase the isotactic content of β‐nucleated polypropylene (β‐iPP) and decrease the cost of its production, the investigation and development of novel highly efficient β‐nucleators are important issues. Nano‐CaCO₃ was used as a support to prepare a supported β‐nucleator, nano‐CaCO₃‐supported calcium pimelate. Fourier transform infrared spectral analysis shows that an in situ chemical reaction takes place between nano‐CaCO₃ and pimelic acid. Differential scanning calorimetry results indicate that the crystallization and melting temperatures of β‐phase in supported β‐nucleator‐nucleated iPP are higher than those of calcium pimelate‐nucleated iPP. The β‐nucleating ability of the supported β‐nucleator is little influenced by the cooling rate and crystallization temperature over a wide range. The decreased content of pimelic acid in the supported β‐nucleator slightly decreases the crystallization temperature of iPP but it has no influence on the content of β‐phase in nucleated iPP. A novel supported β‐nucleator has been successfully synthesized via pimelic acid supported on the surface of CaCO₃. The crystallization temperature of iPP and melting temperature of β‐phase in iPP nucleated using the supported β‐nucleator are higher than those of iPP nucleated using calcium pimelate. The concept of a supported nucleator will provide a new way to increase the efficiency of polymer additives and to decrease the amounts of them that need to be used by using nanoparticles as supports. Copyright © 2010 Society of Chemical Industry     

成核剂对聚丙烯结晶形态和力学性能的影响

研究了聚丙烯(PP)／成核剂共混物的结晶形态及力学性能。结果表明：加入成核剂后，提高PP的结晶温度，加快了结晶速度，使PP球晶细化；成核剂用量在0—0．2份之间时，PP的冲击强度、拉伸强度、硬度、热变形温度均随成核剂用量的增加而提高。     

脱氢枞酸盐透明改性聚丙烯研究

以脱氢枞酸钾和脱氢枞酸钾成核剂对透明聚丙烯（PP）进行改性，研究了脱氢枞酸盐对PP光学性能、力学性能及结晶特性的影响，并与山梨酸类成核剂改性PP的性能进行了比较。实验结果表明，加入脱氢枞酸钾或脱氢枞酸钠后，聚丙烯的雾度大幅度降低，光泽度提高，但透光率变化不大；弯曲模量大幅度提高，而拉伸强度和缺口冲击强度略有下降；球晶尺寸大幅度减小；结晶温度提高，结晶度略有上升。脱氢枞酸盐改性聚丙烯与山梨醇类成核剂改性聚丙烯的性能相当，但脱氢枞酸盐克服了山梨醇类成核剂的缺点，可以作为山梨醇类成核剂的理想替代品。     

Enhanced orientation of the water‐assisted injection‐molded ipp in the presence of nucleating agent

The nucleated isotactic polypropylene (iPP) was molded by water‐assisted injection molding. The crystalline morphology and orientation distribution were studied. The results show that shear brought by melt filling and pressurized water penetration can separately induce the formation of oriented structures in skin region (i.e., the region near mold cavity wall) and the water channel region. For virgin iPP, slightly oriented lamellae appear exclusively in the above aforementioned regions. However, shish‐kebab structure occurs not only in skin and water channel region of the iPP containing moderate content of nucleator (0.2 wt%) but also in the whole region of the iPP containing a higher content of nucleator (1 wt%). It is well known that nucleator cannot directly induce the development of shish‐kebab in the absence of shear, thus the results indicate: shear flow actually distributes over a much broader range than expected; in shear field, nucleator is significantly helpful for the shear which is not sufficient to solely induce oriented structure to promote the formation of the oriented structure. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

山梨醇类成核剂对PP/POE共混体系性能的影响

研究了山梨醇类成核剂ZC-3对PP／POE共混体系性能的影响,并对共混体结晶进行了表征。结果表明：成核剂的加入不仅使PP／POE共混材料韧性提高,同时可改善其刚性,从而使综合力学性能得到平衡,且成核剂的加入使球晶尺寸显著降低,POE在PP中分散更为均匀。POE的理想用量为10％（质量分数）,成核剂ZC-3的最佳用量为0．3％。     

成核剂对聚乙烯蜡结晶形态及熔点的影响

分别以硬脂酸钙、硬脂酸锌、硬脂酸和1,3:2,4-二苄叉山梨醇(ID)为成核剂,采用熔融法对聚乙烯蜡(PEW)进行了重结晶实验,并通过偏光显微镜和显微熔点测定仪研究了成核剂的种类、用量、结晶温度对PEW的结晶形态和熔点的影响.结果表明,成核剂增大了PEW的成核密度,降低了球晶尺寸,提高了熔点;成核剂1,3:2,4-二苄叉山梨醇的效果最好,所形成的晶粒最小,晶片最厚,当其添加量为0.2%,结晶温度为80℃时,PEW的球晶尺寸最小,PEW的初熔点达到了110.6℃,比原料提高了27.7℃.     

Al_2O_3·CaO·SiO_2系统玻璃陶瓷的品化及结构特征

分析了Al2O3,CaO,SiO2系统玻璃陶瓷的品化及结构特征，认为晶核剂及表面核化均可引起玻璃的晶化．表面晶化比晶核剂参与的体积核化容易发生。表面核化不仅由玻璃表面本身具有的活性引起，也可因梯温引起。本系统中，Fe2O3的晶核剂效果比TiO2更强。     

Interactions between sorbitol-type nucleator and additives for polypropylene

The thermal properties of a sorbitol-type nucleating agent (viz. 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol (TBPMN)) were examined in this study, and the influence of common processing additives assessed. In addition, we describe a novel approach to monitor in situ the self-assembly of the nucleator in presence of additives by optical microscopy. The performance of sorbitol compounds is closely associated to their chemical structure and ability to self-assemble. TBPMN formed elongated fibrils from the melt under inert atmosphere, in molted polypropylene, or in presence of antioxidants. However, calcium stearate (CaSt) and glycerol monostearate hampered growth, and yielded thinner fibrils. In presence of the additives, melting point depression of the nucleator occurred, and resulted in a lower degree of crystallinity upon cooling. Performance evaluation of the nucleator in polypropylene blends revealed an increased crystallization temperature when antioxidants were present, while CaSt inhibited nucleator activity. The effect of mono-glycerides was found highly dependent on the processing conditions. Noteworthy, blends containing all the additives displayed the highest performance. This study highlights the importance of the preparation method of polymer additive blends to achieving the best performance in the final product. Characterization was performed by thermogravimetric analysis, Fourier-transform infrared spectroscopy, optical microscopy, and differential scanning calorimetry.     

几种国产聚丙烯透明成核剂性能的研究

研究了采用国产三代山梨醇透明成核DMDBS制备的透明聚丙烯的光学性能、结晶性能、机械性能与热性能。研究表明,在0~2500ppm内随着添加量的增加,国产三代山梨醇透明成核剂与美利肯3988i具有相似的浊度变化曲线。在同样的添加量下,国产三代山梨醇透明成核剂具有与3988i相近的光学性能、结晶性能、机械性能与热变形温度,且无气味,可作为替代进口透明剂、降低生产成本的有效途径。