取代芳基磷酸酯钠盐成核剂的晶体结构与聚丙烯附生结晶的过程

摘要

Single crystal sodium 2,2'-methylene-bis-(4,6-di-t-butylphenylene) phosphonates with two separate crystal structures were prepared through solvent evaporation with methanol and dimethyl formamide(DMF) as solvents,and were characterized by means of single crystal XRD.The results showed that epitaxial crystallization could perform between the lattices of isotactic polypropylene(iPP) and the lattices of NA40-MeOH or NA40-DMF,which indicated that both NA40-MeOH and NA40-DMF had good nucleating ability for iPP.The lengths of the c axes of NA40-MeOH and NA40-DMF were 1.195 0 nm and 1.261 9 nm respectively,two times of the length of the iPP c axis(0.650 nm),and the disregistries were 8.79％ and 3.78％,respectively,which were less than the upper limit of the epitaxial crystallization(10％-15％).The effects of the two nucleating agents on improving the properties of iPP were similar.When the content of the nucleating agents was 0.1％(w),the flexural modulus and tensile strength of iPP increased by about 20％ and 10％,and the particle size of the spherocrystal decreased.%分别以甲醇和N,N-二甲基甲酰胺(DMF)为溶剂,用溶剂挥发法制备两种不同晶体结构的2,2'-亚甲基双(4,6-二叔丁基苯基)磷酸钠(NA40)成核剂单晶.用单晶XRD法确定晶体的晶胞参数,并与等规聚丙烯(iPP)的晶胞参数比较,研究NA40与iPP的附生结晶关系.表征结果显示,NA40-MeOH和NA40-DMF均能与iPP发生附生结晶,有较好的成核性能,c轴长分别为1.195 0 nm和1.261 9 nm,约为iPP晶体c轴(0.650 nm)的2倍,失配率分别为8.79％和3.78％,小于附生结晶能发生的10％～15％失配率上限.两种成核剂对iPP性能的改善作用相近,成核剂用量为0.1％(w)时,较空白iPP的弯曲模量提高约20％,拉伸强度提高10％,球晶尺寸均减小.