Effect of Relative Molecular Weight of MAM on the Structure and Properties of PLA/PBAT/MAM Blends

doi:10.12422/j.issn.1672-6952.2024.01.002

Abstract

Abstract:

Polylactic acid/Poly(butylene adipate?co?terephthalate)/Poly(methyl methacrylate)?b?poly (butyl acrylate)?b?poly (methyl methacrylate)ternary blends (PLA/PBAT/MAM) were prepared by melt blending, and the effect of MAM relative molecular weight on the morphology, structure and properties of the blends was investigated. The results showed that the addition of MAM block copolymer can inhibits the crystallization of PLA，improve the compatibility of PLA/PBAT, reduce the particle size of the dispersed phase and make the distribution more uniform, improve the impact properties and elongation at break of the blends. And the relative molecular weight of MAM increased, the impact strength and elongation at break of the blend increased, the smaller the size of the dispersed phase particles, and the more uniform of particle size distribution.

Key words: Polylactic acid, Poly(butylene adipate?co?terephthalate), Block copolymer, Compatibility, Impact strength, Particle size distribution

摘要：

通过熔融共混法制备聚乳酸/聚己二酸对苯二甲酸丁二酯/聚（甲基丙烯酸甲酯）?b?聚（丙烯酸丁酯）?b?聚（甲基丙烯酸甲酯）（PLA/PBAT/MAM）三元共混物，研究了MAM相对分子质量对PLA/PBAT/MAM三元共混物形态、结构和性能的影响。结果表明，添加MAM嵌段共聚物，能够有效改善PLA与PBAT的相容性，使共混物的玻璃化温度下降，结晶消失，使分散相粒子尺寸下降，分布更加均匀，提高共混物的冲击强度和断裂伸长率；MAM相对分子质量越大，共混物的冲击强度和断裂伸长率越大，分散相粒子尺寸越小，粒径分布越均匀。

关键词: 聚乳酸, 聚己二酸对苯二甲酸丁二酯, 嵌段共聚物, 相容性, 冲击强度, 粒径分布

CLC Number:

TQ322.3

Haifeng ZHANG, Guixin ZHANG, Yuexin HU, Xiangyan HAN, Yuanyuan HAN, Guiyan ZHAO. Effect of Relative Molecular Weight of MAM on the Structure and Properties of PLA/PBAT/MAM Blends[J]. Journal of Liaoning Petrochemical University, 2024, 44(1): 9-14.

张海峰, 张桂鑫, 胡跃鑫, 韩向艳, 韩媛媛, 赵桂艳. MAM相对分子质量对PLA/PBAT/MAM共混物结构与性能的影响[J]. 辽宁石油化工大学学报, 2024, 44(1): 9-14.

Figures/Tables 9

Table 1 The properties of MAM triblock copolymers[20]

种类	$M ¯ n$	$M ¯ w$	T_g/℃
MAM1	25 000	46 000	-26.2
MAM2	44 000	75 000	-34.9
MAM3	82 000	128 000	-39.8

Table 1 The properties of MAM triblock copolymers[20]

种类	$M ¯ n$	$M ¯ w$	T_g/℃
MAM1	25 000	46 000	-26.2
MAM2	44 000	75 000	-34.9
MAM3	82 000	128 000	-39.8

Table 2 The impact properties of PLA and its blends

样品	缺口冲击强度/（kJ•m^-2）
PLA	2.9
80PLA/20PBAT	4.7
80PLA/15PBAT/5MAM1	2.8
80PLA/15PBAT/5MAM2	5.4
80PLA/15PBAT/5MAM3	12.7

Table 3 The tensile properties of PLA and its blends

样品	拉伸弹性模量/MPa	拉伸强度/MPa	断裂伸长率/%
PLA	2 731±103	72.8±1.6	5
80PLA/20PBAT	1 700±23	50.3±3.4	211
80PLA/15PBAT/5MAM1	1 149±31	51.7±2.4	328
80PLA/15PBAT/5MAM2	1 151±44	45.2±0.9	298
80PLA/15PBAT/5MAM3	1 548±24	50.4±1.5	339

Fig.1 The melting curves of PLA and its blends

Table 4 The thermodynamic parameter of PLA and its blends in DSC melting curves

样品	T_g/℃	T_m/℃	T_c/℃	X_c/%
PLA	60.9	148.8	117.7	12.5
80PLA/20PBAT	60.9	150.3	127.2	6.3
80PLA/15PBAT/5MAM1	60.1	—	—	—
80PLA/15PBAT/5MAM2	60.6	—	—	—
80PLA/15PBAT/5MAM3	60.5	—	—	—

Fig.2 The curves of tanδ with temperature of PLA and its blends

Table 5 The DMA data of PLA and its blends

样品	T_g1/℃	T_g2/℃
PLA	-	63.7
80PLA/20PBAT	-27.8	63.2
80PLA/15PBAT/5MAM1	-26.3	63.8
80PLA/15PBAT/5MAM2	-26.4	63.8
80PLA/15PBAT/5MAM3	-25.4	63.9

Fig.3 The SEM images of PLA blends

Table 6 The average particle size and particle size distribution of dispersed phase particles in different samples

样品	d_n/μm	d_w/μm	d_w/d_n
80PLA/20PBAT	1.45	1.76	1.21
80PLA/15PBAT/5MAM1	0.87	0.99	1.14
80PLA/15PBAT/5MAM2	0.57	0.60	1.05
80PLA/15PBAT/5MAM3	0.62	0.66	1.06

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