Nanning Normal University
以木薯淀粉為研究對象，通過熔融共混模壓法制得熱塑性木薯淀粉（TPS）/二氧化硅（SiO2）復合材料。研究超聲作用下不同粒徑（0.02 μm、0.2 μm、23 μm）二氧化硅對熱塑性木薯淀粉的回生熔融焓、回生速率、回生指數及球晶形態結構、接觸角、熱穩定性的影響規律。結果表明，與未超聲樣品相比，利用差示掃描量熱儀（DSC）發現經過超聲作用后TPS/SiO2復合材料的熔融焓增加，回生速率提高、回生指數降低，且添加20 nm SiO2制得產物回生速率提升幅度最大；偏光（PLM）和接觸角測試發現，經過超聲作用后，TPS/SiO2復合材料球晶都變得明顯、水接觸角提高。TG分析表明，超聲作用使復合材料的水分容易揮發，甘油與淀粉的結合能力增強，淀粉的分子結構穩定性增加。SEM分析表明，超聲作用下使得二氧化硅粒子在基體中聚集減少、分散更好；采用FTIR分析發現，復合材料的回生程度增加，雙螺旋結構減少；XRD分析表明，復合材料呈現出A+V晶型，超聲作用后使得V晶型增加、A晶型減少。
The cassava starch as the research object, thermoplastic cassava starch (TPS)/silica (SiO2) composites were prepared by melt blending and molding methods. The effects of different particle sizes (0.02μm、0.2 μm、23 μm) silicon dioxide on the retrogradation melting enthalpy, retrogradation rate, retrogradation index, spherulite morphology, contact angle and thermal stability of thermoplastic cassava starch under ultrasound were studied. The results indicated that comparing with the non-ultrasonic sample, the differential scanning calorimetry (DSC) demonstrated that after ultrasonic treatment, the enthalpy of retrogradation of TPS/SiO2 composites increased, the retrogradation rate enhanced, and the retrogradation index decreased. The retrogradation rate of the product adding 20 nm SiO2 had the largest increase. Polarization (PLM) and water contact angle tests showed that TPS/SiO2 composite spherulite became obvious, and the contact angle increased. TG showed that the ultrasonic action made the moisture of the composite easy to volatilize, the binding ability of glycerol and starch increased, and the molecular structure stability of starch increased. SEM analysis indicated that the silica particles were less aggregated and better dispersed in the matrix under the action of ultrasound. The degree of retrogradation of the composite increased and the double helix structure decreased by FTIR analysis. XRD displayed that the composite presented A+V type crystal formed, and the V type crystal increased and the A type crystal reduced after ultrasonic treatment.