Study on autoclave foaming properties of metallocene polypropylene

doi:10.19491/j.issn.1001-9278.2024.07.010

Abstract

Abstract:

The melting and crystallization behavior of two types of polypropylene， named as mPP and ZNPP， were studied by using differential scanning calorimeter （DSC） and polarized microscope （POM）， and their rheological characteristics were analyzed through frequency scanning and melt stretching. Autoclave foaming experiments were conducted to investigate the melting crystallization behavior， foaming ratio， and cell structure of the expanded polypropylene （EPP） beads. The results indicated that ZNPP had a higher complex viscosity and more obvious shear thinning， leading to higher molecular weight size and distribution. ZNPP exhibits higher melting strength than mPP at higher temperatures due to more intense molecular chain entanglement. However， its melt strength is similar to that of mPP at lower temperatures. The quality of the cell structure needs to be improved， when mPP is used to produce EPP beads with similar ratios to ZNPP.

Key words: metallocene polypropylene, shear thinning, melt strength, autoclave foaming, cell structure

CLC Number:

TQ325.1⁺4

SHEN Qiangfeng, LYU Mingfu, XU Yaohui. Study on autoclave foaming properties of metallocene polypropylene[J]. China Plastics, 2024, 38(7): 55-61.

Figures/Tables 13

References 23

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样品	M_n	M_w	M_z+1	M_w/M_n
MAOPP	7.90×10⁴	2.66×10⁵	8.58×10⁵	2.97
ZNPP	6.66×10⁴	2.84×10⁵	1.21×10⁶	4.28

样品	M_n	M_w	M_z+1	M_w/M_n
MAOPP	7.90×10⁴	2.66×10⁵	8.58×10⁵	2.97
ZNPP	6.66×10⁴	2.84×10⁵	1.21×10⁶	4.28

样品	T_m/℃	ΔH_m/J·g^-1	T_c/℃	ΔH_c/ J·g^-1	X_c /%
MAOPP	143.91	85.88	110.43	83.23	41.09
ZNPP	143.32	65.65	100.98	73.27	31.41

样品	T_m/℃	ΔH_m/J·g^-1	T_c/℃	ΔH_c/ J·g^-1	X_c /%
MAOPP	143.91	85.88	110.43	83.23	41.09
ZNPP	143.32	65.65	100.98	73.27	31.41

样品	发泡倍率	T_m1/℃	ΔH_m1/ J·g^-1	T_m1/℃	ΔH_m1/ J·g^-1
MAOEPP1	4.6	140.7	54.6	156.6	16.8
MAOEPP2	11.2	141.4	55.9	156.7	12.2
MAOEPP3	18.5	142.3	60.3	157.0	8.9
ZNEPP3	18.6	137.4	43.1	159.3	11.6