纤维增强尿素和甲酰胺混合塑化热塑性淀粉

Microfibrils as Reinforcement for Thermoplastic Starch Plasticized with the Mixture of Formamide and Glycerol

使用尿素和甲酰胺混合塑化剂制备的热塑性淀粉(UFPTPS)可以有效抑制淀粉的回生。用这种热塑性淀粉作为短棉绒纤维的基质,制备的纤维增强热塑性淀粉(FRTPS)可以提高其力学性能和耐水性能。扫描电镜显示了短棉绒纤维较好地分散在UFPTPS中,纤维和淀粉结合良好。X ray衍射说明加入纤维后作为基质的UFPTPS仍可以抑制淀粉回生。纤维质量分数对FRTPS力学性能影响的研究显示,随着w(纤维)=0%提高到20%,FRTPS拉伸强度翻番达到10 16MPa,杨氏模量达到97 85N/mm2;伸长率从105%降到17%,断裂能从2 158N·m降到0 573N·m。随着水质量分数的增加,增强效应逐渐被弱化,在高水含量[w(水)>30%]时,水分和纤维质量分数对强度没有影响。FRTPS与UFPTPS相比,耐水性明显提高。

Thermoplastic starch (TPS) plasticized with mixture of urea and formamide (UFPTPS)could effectively restrain the starch retrogradation.This paper reports the properties of TPS composites,which were prepared with urea and formamide as the mixed plasticizer and microfibrils as reinforcement in order to improve the mechanical properties and water resistance of TPS.Scanning electron microscope showed the dispersion of microfibrils in TPS and good adhesion between starch and microfibrils.X-ray diffraction illustrated that when microfibrils were introduced into the matrix of UFPTPS,UFPTPS could still restrain the starch retrogradation.The dependence of mechanical properties of reinforced TPS on the contents of microfibril and water was studied.With the increase of microfibril contents from 0 to 20%,the tensile strength of the composites was doubled to 10.16 MPa and Youngs modulus to 97.85 N/mm^2,while the elongation was reduced from 105% to 17% and breaking energy from 2.158 N·m to 0.573 N·m.With increasing water content,the reinforcement effect was gradually weakened.When the water content reached 30%,both water content and microfibril content had little effect on the tensile strength.The reinforced TPS ameliorated the tensile strength,Youngs modulus and water resistance.