滑石粉和PLA-g-MAH对聚乳酸结晶性能和熔体强度的改善

doi:10.7503/cjcu20180006

摘要/Abstract

摘要：

采用混沌混炼单螺杆挤出机, 制备马来酸酐接枝聚乳酸(PLA-g-MAH), 进而制备PLA/滑石粉(5%, 10%和20%, 质量分数)和PLA/滑石粉(20%)/PLA-g-MAH(5%和10%)复合材料. 复合材料样品中滑石粉的分散状态良好, 滑石粉含量高达20%时未发生团聚. 20%滑石粉和10% PLA-g-MAH使复合材料中PLA的α晶含量明显增加, 结晶度提高至31.6%. 在175 ℃下, PLA样品的熔体强度仅为3.6 mN, 20%滑石粉明显提高了PLA的熔体强度(11.6 mN), 这是由于分散较均匀的片状滑石粉对PLA熔体起增强效应并可提高PLA结晶速率, 对PLA结晶有促进效应. 与PLA样品对比, PLA/滑石粉(20%)/PLA-g-MAH(5%)复合材料的杨氏模量和冲击强度分别提高了51.7%和16.9%.

关键词: 聚乳酸, 滑石粉, 马来酸酐, 复合材料, 结晶性能, 熔体强度

Abstract:

Talc and PLA-g-maleic anhydride(PLA-g-MAH) were added to polylactide(PLA) to simultaneously improve its melt strength, crystallinity(X_c) and mechanical properties. Using a single-screw extruder with a chaotic mixing screw developed in our group, the PLA-g-MAH was prepared via reactive extrusion. Its grafting rate is measured to be 1%. Then, a series of PLA/talc(5%, 10% and 20%, mass fraction) and PLA/talc(20%, mass fraction)/PLA-g-MAH(5% and 10%, mass fraction) composites were prepared using the same extruder. The chaotic mixing in the extruder effectively improves the dispersion of the talc in the PLA matrix, and the talc of up to 20% almost does not agglomerate. Adding the PLA-g-MAH into the composites reduces the voids and the gaps around the talc on the cyrofractured surfaces and improves the interfacial adhesion between the PLA and talc. For the PLA/talc(20%) composite samples with 10% PLA-g-MAH, the α crystal content of the PLA is increased obviously and its X_c is increased to 31.6%. At 175 ℃, the melt strength for the PLA sample is relatively low(3.6 mN), and it is obviously enhanced(11.6 mN) for the composite sample with 20% talc. The explanation for this is as follows. The well dispersed talc has a reinforcing effect on the PLA melt and increases the crystallization behavior of PLA; moreover, the draw-down force can improve both effects of the orientation-induced PLA crystallization and the increased PLA crystallization behavior by the added talc. Compared with the PLA sample, the PLA/talc(20%)/PLA-g-MAH(5%) sample exhibits increments of 51.7% and 16.9% for the Young’s modulus and impact strength, respectively.

Key words: Poly(lactic acid), Talc, Maleic anhydride, Composite, Crystallization behavior, Melt strength

TrendMD:

韩嘉晖, 黄汉雄, 黄宇霄. 滑石粉和PLA-g-MAH对聚乳酸结晶性能和熔体强度的改善. 高等学校化学学报, 2018, 39(9): 2089.

HAN Jiahui,HUANG Hanxiong,HUANG Yuxiao. Improving Crystallization Behavior and Melt Strength of Poly(lactic acid) via Adding Talc and PLA-g-MAH^†. Chem. J. Chinese Universities, 2018, 39(9): 2089.

图/表 14

Table 1 Mass fraction of samples

Sample	w(PLA)(%)	w(Talc)(%)	w(PLA-g-MAH)(%)
PLA	100	0	0
PLA/T5	95	5	0
PLA/T10	90	10	0
PLA/T20	80	20	0
PLA/T20/M5	75	20	5
PLA/T20/M10	70	20	10

Fig.1 FTIR spectra of PLA(a) and PLA-g-MAH(b) samples

Fig.2 SEM images of cyrofractured surfaces for PLA/T5(A), PLA/T10(B) and PLA/T20(C) composite samples

Fig.3 SEM images of cyrofractured surfaces for PLA/T20/M5(A) and PLA/T20/M10(B) composite samples

Scheme 1 Schematics of mechanism for compatibilizing PLA and talc by PLA-g-MAH

Fig.4 DSC curves of PLA and PLA/talc composite samples (A) Second heating scans; (B) cooling scans. a. PLA; b. PLA/T5; c. PLA/T10; d. PLA/T20; e. PLA/T20/M5; f. PLA/T20/M10.

Table 2 Thermal analysis data for PLA and PLA/talc composite samples

Sample	T_g/℃	T_cc/℃	X_cc(%)	T_m1/℃	T_m2/℃	X_c(%)
PLA	59.6	109.8	27.9	152.9	159.7	—
PLA/T5	60.0	101.7	15.0	151.5	158.7	15.2
PLA/T10	59.8	99.1	7.6	152.2	158.7	19.8
PLA/T20	59.8	96.6	4.5	151.7	158.7	25.1
PLA/T20/M5	59.6	96.5	2.8	152.9	160.3	27.2
PLA/T20/M10	59.8	—	—	154.4	162.1	31.6

Fig.5 Relative crystallinity versus crystallization time curves for PLA/talc composite samples a. PLA/T5; b. PLA/T10; c. PLA/T20; d. PLA/T20/M5; e. PLA/T20/M10.

Table 3 Crystallization half-time(t1/2) and Jeziorny-modified-Avrami crystallization kinetic parameters for PLA/talc composite samples

Sample	t_1/2/min	n	K/mi $n - n$	K_c/mi $n - n$
PLA/T5	1.38	2.60	0.3217	0.8928
PLA/T10	1.13	2.64	0.5284	0.9382
PLA/T20	1.09	2.76	0.5672	0.9449
PLA/T20/M5	0.92	2.37	0.8831	0.9876
PLA/T20/M10	0.76	2.67	1.4421	1.0373

Table 3 Crystallization half-time(t1/2) and Jeziorny-modified-Avrami crystallization kinetic parameters for PLA/talc composite samples

Sample	t_1/2/min	n	K/mi $n - n$	K_c/mi $n - n$
PLA/T5	1.38	2.60	0.3217	0.8928
PLA/T10	1.13	2.64	0.5284	0.9382
PLA/T20	1.09	2.76	0.5672	0.9449
PLA/T20/M5	0.92	2.37	0.8831	0.9876
PLA/T20/M10	0.76	2.67	1.4421	1.0373

Fig.6 XRD patterns for PLA and PLA/talc composite samples a. PLA; b. PLA/T5; c. PLA/T10; d. PLA/T20; e. PLA/T20/M5; f. PLA/T20/M10.

Fig.7 Draw-down force versus draw ratio(A) and extensional viscosity versus extensional strain rate curves(B) for PLA and PLA/talc composite samples a. PLA; b. PLA/T20; c. PLA/T20/M5; d. PLA/T20/M10.

Fig.8 Storage modulus(A) and tanδ versus temperature curves(B) for PLA and PLA/talc composite samples a. PLA; b. PLA/T20; c. PLA/T20/M5; d. PLA/T20/M10.

Fig.9 Young’s moduli(A) and tensile strengths(B) of PLA and PLA/talc composite samples a. PLA; b. PLA/T5; c. PLA/T10; d. PLA/T20; e. PLA/T20/M5; f. PLA/T20/M10.

Fig.10 Notched Izod impact strengths of PLA and PLA/talc composite samples a. PLA; b. PLA/T5; c. PLA/T10; d. PLA/T20; e. PLA/T20/M5; f. PLA/T20/M10.

参考文献 33

[1]	Drumright R. E., Gruber P. R., Henton D. E., Adv. Mater., 2000, 12(23), 1841—1846
[2]	Li G. L., Huang J. J., Zhuang H. H., Yuan Z. S., Shao C. G., Ying J., Wang Y. M., Cao W., Liu C. T., Shen C. Y., Chem. J. Chinese Universities, 2017, 38(9), 1663—1669
	(李桂丽, 黄静静, 张欢欢, 袁朝圣, 邵春光, 应进, 王亚明, 曹伟, 刘春太, 申长雨. 高等学校化学学报, 2017, 38(9), 1663—1669)
[3]	Li Y. J., Shimizu. H., Macromol. Biosci., 2007, 7(7), 921—928
[4]	Han J. J., Huang H. X., J. Appl. Polym. Sci., 2011, 120(6), 3217—3223
[5]	Zhao F., Huang H. X., Zhang S. D., J. Appl. Polym. Sci., 2015, 132(48), doi/10.1002/app.42511
[6]	Xiong Z. J., Zhang X. Q., Liu G. M., Zhao Y., Wang R., Wang D. J., Chem. J. Chinese Universities, 2013, 34(5), 1288—1294
	(熊祖江, 张秀芹, 刘国明, 赵莹, 王锐, 王笃金. 高等学校化学学报, 2013, 34(5), 1288—1294)
[7]	Wang Y. Y., Song Y. M., Du J., Xi Z. H., Wang Q. W., Materials, 2017, 10(9), doi/org/10.3390/ma10090999
[8]	Zhou M., Zhou P., Xiong P., Qian X., Zheng H.H., Macromol. Res., 2015, 23(3), 231—236
[9]	Lai X. L., Yang W., Wang Z., Shi D. W., Liu Z. Y., Yang M. B., J. Appl. Polym. Sci., 2018, 135, doi/10.1002/app.45675
[10]	Nofar M., Mater. Design., 2016, 101, 24—34
[11]	Jain S., Misra M., Mohanty A K., Ghosh A. K., J. Polym. Environ., 2012, 20(4), 1027—1037
[12]	Shakoor A., Thomas N.L., Polym. Eng. Sci., 2014, 54(1), 64—70
[13]	Kaynak C., Erdogan A.R., Polym. Adv. Technol., 2015, 27(6), 812—822
[14]	Zhang S. D., Huang H. X., Jiang G., Polym. Renew. Resour., 2013, 4(4), 153—168
[15]	Zhu R., Liu H. Z., Zhang J. W., Ind. Eng. Chem. Res., 2012, 51(22), 7786—7792
[16]	Kaynak C., Meyva Y., Polym. Adv. Technol., 2015, 25(12), 1622—1632
[17]	Ouchiar S., Stoclet G., Cabaret C., Georges E., Smith A., Martias C., Addad A., Gloaguen V., Appl. Clay. Sci., 2015, 116/117, 231—240
[18]	Jiang G., Huang H. X., Chen Z. K., Polym. Plast. Technol., 2011, 50(10), 1035—1039
[19]	Fowlks A. C., Narayan R., J. Appl. Polym. Sci., 2010, 118(5), 2810—2820
[20]	Barletta M., Pizzi E., Puopolo M., Vesco S., Daneshvar-Fatah F., J. Appl. Polym. Sci., 2017, 134(32), doi/10.1002/app.45179
[21]	Hua C., Chen F., Wang H., Liu Z., Yang W., Yang M., Acta Polym. Sin., 2016, (8), 1136—1144
	(华笋, 陈风, 王捍卿, 刘正英, 杨伟, 杨鸣波. 高分子学报, 2016, (8), 1136—1144)
[22]	Yu T., Jiang N., Li Y.,Compos. Part A: Appl. S., 2014, 64(21), 139—146
[23]	Li M., Hu D., Wang Y. M., Shen C. Y., Polym. Eng. Sci., 2010, 50(12), 2298—2305
[24]	Mo Z.S., Acta Polym. Sin., 2008, (7), 656—661
	(莫志深. 高分子学报, 2008, (7), 656—661)
[25]	Kawai T., Rahman N., Matsuba G., Nishida K., Kanaya T., Nakano M., Okamoto H., Kawada J., Usuki A., Honma N., Nakajima K., Matsuda M., Macromolecules, 2007, 40, 9463—9469
[26]	Xu L. Q., Huang H. X., Ind. Eng. Chem. Res., 2014, 53(6), 2277—2286
[27]	Shao W. G., Wang Q., Li K. S., Polym. Eng. Sci., 2005, 45(4), 451—457
[28]	Wagner M. H., Bernnat A., Schulze V., J. Rheol., 1997, 42(4), 917—928
[29]	Botta L., Scaffaro R., Mantia F. P. L., Dintcheva N. T., J. Polym. Sci. Polym. Phys., 2010, 48, 344—355
[30]	Bangarusampath D. S., Ruckdaschel H., Altstadt V., Sandler J. K. W., Garray D., Shaffer M. S. P., Polymer, 2009, 50, 5803—5811
[31]	Wang Q. J., Huang H. X., Polym. Test., 2013, 32, 1400—1407
[32]	Singh V. P., Vimal K. K., Kapur G. S., Sharma S., Choudhary V., J. Polym. Res., 2016, 23(43), 1—17
[33]	Lee S. H., Cho E., Youn R. J., J. Appl. Polym. Sci., 2006, 103, 3506—3515