无机纳米材料增强尿素和甲酰胺混合塑化热塑性淀粉

Inorganic Nano-stuffs as Reinforcement for Thermoplastic Starch Plasticized with the Mixture of Formamide and Urea

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重结晶,用这种热塑性淀粉作为纳米S iO2或纳米CaCO3的基质,制备了无机纳米增强热塑性淀粉(NRTPS)。扫描电镜(SEM)显示了纳米S iO2和CaCO3含量对UFPTPS塑化后微观形貌的影响。红外光谱(FTIR)显示了纳米S iO2或CaCO3和淀粉可以发生作用,淀粉与纳米S iO2的相互作用要大于纳米CaCO3。X射线衍射说明,加入纳米S iO2或纳米CaCO3后,作为基质的UFPTPS仍可以抑制淀粉重结晶。纳米S iO2和纳米CaCO3均对UFPTPS起到增强的作用,在w(H2O)=10%时,S iO2增强UFPTPS的强度由UFPTPS的5.67 MPa增加到9.67 MPa;CaCO3增强UFPTPS的强度由UFPTPS的5.67 MPa增加到8.61 MPa。水含量再增加,增强效应逐渐弱化,w(H2O)>23%后,水分对材料力学性能影响很小。与UFPTPS相比,NRTPS耐水性明显提高,在100%相对湿度下,S iO2增强UFPTPS材料在w(S iO2)=1%时材料耐水性最好,平衡时w(H2O)=45%;CaCO3增强UFPTPS材料耐水性随着CaCO3含量增加而提高,w(CaCO3)=3%时材料耐水性最好,平衡时w(H2O)=41%。

Thermoplastic starch plasticized with the mixture of urea and formamide （UFPTPS） could effectively restrain the starch retrogradation, and nano-SiO2 or CaCO3 was used as the reinforcement. SEM showed the dispersion of nano-SiO2 or CaCO3 in UFPTPS, FTIR revealed that there exist the interaction between SiO2 or CaCO3 and starch; moreover the interaction between SiO2 and starch is stronger. XRD illustrated that when nano-stuffs were introduced into the matrix of UFPTPS, the starch retrogradation can still be restrained, At w（ H2O） = 10% , the tensile stress was increased from 5.67 MPa of UFPTPS to 9.67 MPa of SiO2-reinforced UFPTPS,or 8.61 MPa of CaCO3-reinforced UFPTPS. With increasing water contents, the reintorcement effect was gradually weakened. At w （H2O） 〉 23% , water had little effect on the tensile stress and strain. Compared with UFPTPS, nano-SiO2 or CaCO3- reinforced UFPTPS had better water resistance, At w （ SiO2 ） = 1% , SiO2-reinforced UFPTPS had optimal water resistance with w（ equilibrium water） =45%, At w（ CaCO3 ） = 3% , CaCO3- reinforced UFPTPS had optimal water resistance with w（ equilibrium water） = 41%.