Microstructure characterization and thermal stability of new silk fibroin composite films

doi:10.11949/0438-1157.20191317

Abstract

Abstract:

Silk fibroin-based polymer composites can be widely used in the fields of tissue engineering, biomedicine, and semiconductor materials. In this study, a novel silk fibroin/polylactic acid biocomposite film was prepared by physical-blending technique. Scanning electron microscope(SEM), Fourier transform infrared analysis(FTIR), Raman spectroscopy, X-ray diffraction (XRD) and thermal analysis were used to characterize the morphology, structure, phase components and thermal stability of the composite films with different proportions, and to explore their microstructure, interaction mechanism and thermal stability. The results showed that with the increase of silk fibroin content, the content of β-sheet increased, the content of α-helix and random coils decreased, and the glass transition temperature increased. Due to the interaction between silk fibroin and polylactic acid, which improved the thermal stability of the composite film.

Key words: silk fibroin, polylactic acid, composite materials, microscale, crystallization

摘要：

基于丝素的高分子复合材料可以广泛地应用于组织工程、生物医药和半导体材料等领域。通过物理-共混技术制备了一种新型生物高分子丝素/聚乳酸复合膜。利用扫描电镜、傅里叶红外光谱、拉曼光谱、X射线衍射和热分析技术对其形貌、结构和相态组分以及热稳定性进行了表征，探究了不同比例复合膜的微结构、相互作用机理和热稳定性。结果表明：随着丝素含量的增加，复合膜中的β-折叠含量增多，α-螺旋和无规卷曲含量减少，玻璃化转变温度提高；由于丝素与聚乳酸间的相互作用，提高了复合膜的热稳定性。

关键词: 丝素蛋白, 聚乳酸, 复合材料, 微尺度, 结晶

CLC Number:

TQ 317

Yingying LI, Qianqian DENG, Hao LIU, Qichun LIU, Zhenggui GU, Fang WANG. Microstructure characterization and thermal stability of new silk fibroin composite films[J]. CIESC Journal, 2020, 71(1): 388-396.

李莹莹, 邓谦谦, 刘浩, 刘其春, 顾正桂, 王昉. 新型丝素复合膜的微结构表征及热稳定性[J]. 化工学报, 2020, 71(1): 388-396.

Figures/Tables 8

Fig.1 SEM of MSF/PLA composite film prepared with different mass ratios(The upper layer a—e are silk fibroin/polylactic acid mixed solution, MSF/PLA-0∶5, MSF/PLA-1∶5, MSF/PLA-5∶5, MSF/PLA-5∶1 and MSF/PLA-5∶0, respectively; The lower layer a'—e' are SEM images corresponding to the ratio of the silk fibroin and polylactic acid composite films, respectively)

Fig.2 FTIR spectra of MSF/PLA composite films with different mass ratios

Table 1 Contents of silk fibroin protein in composite materials

Sample	β-sheet/%	α-helix & random coils /%	Turns/%	Side chains/%
MSF/PLA-1∶5	12.23	73.89	12.56	1.32
MSF/PLA-5∶5	15.54	71.03	10.79	2.64
MSF/PLA-5∶1	18.24	68.99	9.56	3.21
MSF/PLA-5∶0	23.29	66.80	8.55	1.36

Fig.3 Raman spectra of MSF/PLA composite films with different mass ratios

Fig.4 XRD spectra of MSF/PLA composite films with different mass ratios

Table 2 Thermodynamic parameters, phase component content and TG data of composite film

Item	MSF/PLA-0∶5	MSF/PLA-1∶5	MSF/PLA-5∶5	MSF/PLA-5∶1	MSF/PLA-5∶0
T_g/℃	55.81	58.68	65.02	74.33	154.32
T_m /℃	150.29	150.01	147.11	144.98	—
ΔH_m/(J·g^-1)	30.23	25.37	18.68	14.57	—
ΔC_p/(J·g^-1·℃^-1)	0.39	0.40	0.43	0.46	—
X_C-DSC	0.33	0.27	0.19	0.11	—
X_MAP-DSC	0.63	0.66	0.70	0.75	—
X_RAP-DSC	0.04	0.07	0.11	0.14	—
X_C-XRD	0.35	0.30	0.21	0.12	—
X_MAP-XRD	0.59	0.63	0.69	0.74	—
X_RAP-XRD	0.06	0.07	0.10	0.14	—
T_onset /℃	346.27	330.19	305.38	283.37	272.76
T_p/℃	350.69	336.95	316.06	289.62	280.27
ΔY_w /%	0.42	1.73	4.80	6.07	6.99

Fig.5 SSDSC reversible specific heat curve of MSF/PLA-1∶5 composite film

Fig.6 Thermogravimetric curve of MSF/PLA composite material

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