The crystallization behavior of long chain branched polypropylene (LCBPP) and linear isotactic polypropylene (PP) was studied by DSC

WAXD and POM.The results of WXAD and DSC showed that the LCB structure was conductive to -crystal crystallization

a little of -crystal appeared in LCBPP samples.The results of POM and DSC verified that the LCB structure can perform the function of promoting heterogeneous nucleation and decreasing crystal size.Compared with pure PP

the crystallization temperature and crystallization rate of LCBPP increased.The crystal size of LCBPP decreased with the increased branching content.The higher crystallization temperature and faster crystallization rate of LCBPP were in favor of bubble curing and increased the maximum foaming temperature.In addition

because of the higher melt strength of LCBPP

the LCBPP showed bigger expanding ratio than linear PP at the same foaming condition.The results of batch foaming with supercritical CO2 as blowing agent at 18 MPa showed that the LCBPP displayed a better foamability than linear PP.The LCBPP exhibited a wide foaming temperature window (about 5 K) while linear PP exhibited a very narrow foaming temperature window (about 2 K) and the maximum expantion ratio of LCBPP was 25.8 while the maximum expantion ratio of linear PP was only 18.6.