Study on Surface Modification of Thermoplastic Starch Plastics through Photo⁃crosslinking at Different Ultraviolet Wavelengths

doi:10.19491/j.issn.1001-9278.2020.06.007

Abstract

Abstract:

To improve the mechanical and water?resistant properties of thermoplastic starch plastics (TPS), a photo?crosslinking modification was conducted on the surface of TPS with 2,4,6?trimethylbenzoyldiphenyl phosphine oxide as a photoinitiator under the ultraviolet (UV) irradiation at different wavelengths. The effect of UV wavelength on the cross?linking degree, stretching performance, dynamic mechanic properties and water?resistance of modified TPS was investigated. The results indicated that the modified TPS achieved the maximum tensile strength of 4.1 MPa, flexural strength of 2.7 MPa, and impact strength of 96.8 kJ/m². The modified TPS exhibited two glass transition temperatures at -37.48 and 50.32 °C in the starch and glycerol domains, respectively. Moreover, a maximum contact angle of 75 °C was obtained for the modified TPS, and their water resistance was improved remarkably. The characterization of cross?linking degree further confirmed that the TPS gained an optimum crosslinking structure.

Key words: thermoplastic starch：ultraviolet light, photocrosslinking, modification

CLC Number:

TQ321

Chunhao CHEN, Zhongmei MIAO, Menghua XI, Bin GUO, Yanan HUANG. Study on Surface Modification of Thermoplastic Starch Plastics through Photo⁃crosslinking at Different Ultraviolet Wavelengths[J]. China Plastics, 2020, 34(6): 40-44.

Figures/Tables 8

References 15

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紫外光波长/nm	拉伸强度/MPa	弯曲强度/MPa	冲击强度/kJ^.m^-2
未光照	2.9±0.1	1.1±0.1	56.2±1.5
254	3.8±0.1	2.5±0.1	75.7±1.7
308	4.1±0.1	2.7±0.2	96.8±2.0
365	3.3±0.2	2.2±0.2	69.0±3.9

紫外光波长/nm	拉伸强度/MPa	弯曲强度/MPa	冲击强度/kJ^.m^-2
未光照	2.9±0.1	1.1±0.1	56.2±1.5
254	3.8±0.1	2.5±0.1	75.7±1.7
308	4.1±0.1	2.7±0.2	96.8±2.0
365	3.3±0.2	2.2±0.2	69.0±3.9

紫外光波长/nm	T_β/℃	T_α/℃
未光照	-40.57	35.34
254	-40.51	47.27
308	-37.48	50.32
365	-39.46	45.17

紫外光波长/nm	T_β/℃	T_α/℃
未光照	-40.57	35.34
254	-40.51	47.27
308	-37.48	50.32
365	-39.46	45.17

紫外光波长/nm	C₁	C₂	t₀/h^1/2	M_∞/%
未光照	-4.272 7	8.158 4	2.774 4	6.005 1
254	-1.909 1	6.261 0	6.841 6	5.585 8
308	-1.241 8	5.275 4	7.825 2	5.217 0
365	-2.760 1	5.884 26	4.306 3	5.697 2