PET成核剂研究和应用进展

 PET成核剂被用来改善PET晶粒结构、提高结晶速率、增强机械性能、缩短成型周期。常用的PET成核剂可以分为无机成核剂、有机成核剂和复合型成核剂三大类。无机成核剂是应用最早的成核剂，主要有黏土，包括蒙脱土、水滑石等；金属氧化物，包括SiO2、MgO、ZnO、TiO2等；无机盐，包括Na2CO3、NaHCO3、BaSO4等；非碱金属氢氧化物，包括Al(OH)3、Mg(OH)2等。无机类成核剂简单易得，成本低廉。使用简便，但此类成核剂属于异相成核剂，分散性差，成核效果一般；有机类成核剂主要包括苯甲酸盐、乙二胺、离聚物等，其与PET相容性高，成核效果较好，但价格相对较高；复合型成核剂为两种或两种以上不同成核剂复配，例如NaCl/PEO、PEG4000/RCOO-Na+、苯甲酸钠/Surlyn/DER等，不同成核剂之间通常具有协同效应，同时表现出不同成核剂的优点，并且在性能和成本方面具有优势。因此，复合成核剂将成为研究的热点，复合方法、复合工艺、改性机制等将成为复合成核剂研究的方向。

Progress in Researches and Applications of Nucleating Agents for Polyethylene Terephthalate

PET nucleating agents are used to improve the crystal structure, increase the crystallization rate, improve the physical-mechanical properties and shorten the forming period. The most common PET nucleating agents fall into three groups: inorganic nucleating agents, organic nucleating agents and composite nucleating agents. Inorganic nucleating agents including clay (montmorillonite, layered double hydroxide, etc.), metallic oxide (SiO2, MgO, ZnO, TiO2, etc.), non-alkali metal hydroxides (Al(OH)3, Mg(OH)2, etc.) and inorganic salts (Na2CO3, NaHCO3, BaSO4, etc.) are the earliest nucleating agents to be used and enjoy the advantages of being cheap, easy to obtain and easy to be use. They are heterogeneous in PET, and are difficult to disperse uniformly. Organic nucleating agents include organic acid salts (benzoate, sodium formate, sodium acetate, etc.) ionomer and others. They are easy to disperse in the polymer, with good performances. Composite nucleating agents possess both advantages of organic and inorganic nucleating agents. The synergistic effect is obvious and the performances are excellent. Therefore, the composite nucleating agents will become a focus of researches for the mechanism and applications.