Regulation of structure and mechanical properties of poly(propylene-butene) alloys by monomer composition switching

doi:10.11949/0438-1157.20221523

Abstract

Abstract:

In order to solve the problem of low impact strength of polypropylene (PP) materials and utilize a large number of cheap 1-butene resources in China, the monomer composition switching method was used to carry out bulk homopolymerization of propylene and bulk copolymerization of propylene/butene in the reactor, and in situ preparation of polypropylene alloy. The obtained polypropylene alloys were mainly composed of propylene-butylene random copolymer, propylene-butylene block copolymer with long PP segments and high isotacticity polypropylene. As the rubber phase, the copolymer was dispersed in the polypropylene matrix to form a sea-island structure, which acted as the loci for stress concentration to induce and terminate crazes, and absorb impactive energy. The block copolymer with long PP segments increased the compatibility between the rubber phase and the matrix, resulting in the alloy material with balanced toughness and stiffness. The impact strength of the alloy was up to 48.91 kJ/m². The influences of the polymerization conditions on the alloy composition were investigated. The relationship between the alloy composition, phase morphology and mechanical properties was revealed.

Key words: polymers, monomer composition switching, poly(propylene-butene) alloys, morphology, mechanical properties

摘要：

为解决聚丙烯材料抗冲击强度低的问题，同时利用国内大量廉价的1-丁烯资源，采用单体组成切换法在反应器内进行丙烯本体均聚和丙烯/丁烯本体共聚，原位制备聚丙烯合金。该合金主要由丙丁无规共聚物、长丙烯链段的丙丁嵌段共聚物和高等规度的聚丙烯组成。共聚物作为橡胶相分散在聚丙烯基体中，形成海岛结构，充当应力集中点，起到诱发及终止银纹、吸收能量的作用。长丙烯链段的嵌段共聚物增加了橡胶相与基体的相容性，使合金材料具有优异的刚性和韧性平衡，材料的抗冲击强度最高达48.91 kJ/m²。本文探究了聚合工艺对合金组成结构的影响，并揭示了合金组成结构和相形态、力学性能的关系。

关键词: 聚合物, 单体组成切换, 聚丙烯/丁烯合金, 形态学, 力学性能

CLC Number:

TQ 325.1

Shaojie ZHENG, Jianbin WANG, Jijiang HU, Bo-Geng LI, Wenbo YUAN, Zong WANG, Zhen YAO. Regulation of structure and mechanical properties of poly(propylene-butene) alloys by monomer composition switching[J]. CIESC Journal, 2023, 74(2): 904-915.

郑少杰, 王建斌, 胡激江, 李伯耿, 袁文博, 王宗, 姚臻. 单体组成切换法调控聚丙烯/丁烯合金的结构与性能[J]. 化工学报, 2023, 74(2): 904-915.

Figures/Tables 20

References 30

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样品	切换频率	预聚时间/min	丙烯加入量/kg	丁烯加入量/kg	H₂/L	催化活性/ (kg/(g·h))
PcoB1	—	0	2	0.6	0	182.7
PcoB2	—	0	2	0.6	1.0	277.9
PP-PB1	—	0	2	0.6	0	192.8
PP-PB2	—	0	2	0.6	1.0	248.7
MS1	1	0	2	0.6	0	191.6
MS2	2	0	2	0.6	0	182.7
MS3	3	0	2	0.6	0	220.8
MS4	4	0	2	0.6	0	184.0
MS5	5	0	2	0.6	0	185.2
MS6	1	0	2	0.6	1.0	276.6
MS7	2	0	2	0.6	1.0	272.8
MS8	3	0	2	0.6	1.0	284.2
MS9	4	0	2	0.6	1.0	281.7
MS10	5	0	2	0.6	1.0	270.2
MS11	3	30	2	0.6	0.3	277.9
MS12	3	30	2	0.6	0.6	279.1
MS13	3	30	2	0.6	1.0	305.8
MS14	3	30	2	0.4	0.6	265.2
MS15	3	30	2	0.5	0.6	253.7
MS16	3	30	2	0.7	0.6	286.7

样品	切换频率	预聚时间/min	丙烯加入量/kg	丁烯加入量/kg	H₂/L	催化活性/ (kg/(g·h))
PcoB1	—	0	2	0.6	0	182.7
PcoB2	—	0	2	0.6	1.0	277.9
PP-PB1	—	0	2	0.6	0	192.8
PP-PB2	—	0	2	0.6	1.0	248.7
MS1	1	0	2	0.6	0	191.6
MS2	2	0	2	0.6	0	182.7
MS3	3	0	2	0.6	0	220.8
MS4	4	0	2	0.6	0	184.0
MS5	5	0	2	0.6	0	185.2
MS6	1	0	2	0.6	1.0	276.6
MS7	2	0	2	0.6	1.0	272.8
MS8	3	0	2	0.6	1.0	284.2
MS9	4	0	2	0.6	1.0	281.7
MS10	5	0	2	0.6	1.0	270.2
MS11	3	30	2	0.6	0.3	277.9
MS12	3	30	2	0.6	0.6	279.1
MS13	3	30	2	0.6	1.0	305.8
MS14	3	30	2	0.4	0.6	265.2
MS15	3	30	2	0.5	0.6	253.7
MS16	3	30	2	0.7	0.6	286.7

编号	化学位移	三单体序列结构	对应的碳
1	47.20	PPB	P-S_αα
2	46.87	PPB+PPP	P-S_αα
3	46.59	PPP	P-S_αα
4	43.76	BPB	P-S_αα
5	40.31	BBB	B-S_αα
6	35.05	BBB	B-T_ββ
7	28.94	PPP	P-T_ββ
8	28.54	PBP	B-T_ββ
9	28.12	PBB	B-T_ββ

编号	化学位移	三单体序列结构	对应的碳
1	47.20	PPB	P-S_αα
2	46.87	PPB+PPP	P-S_αα
3	46.59	PPP	P-S_αα
4	43.76	BPB	P-S_αα
5	40.31	BBB	B-S_αα
6	35.05	BBB	B-T_ββ
7	28.94	PPP	P-T_ββ
8	28.54	PBP	B-T_ββ
9	28.12	PBB	B-T_ββ

Sample	Triad sequences/%(mol)						Dyad sequences/%(mol)			Monomer/%(mol)
Sample	PPP	PPB	PBP	PBB	BPB	BBB	PP	PB	BB	P	B
MS16	70.2	15.6	5.0	1.5	2.7	5.0	78.0	16.2	5.8	86.1	13.9