预/共辐照条件下改性塑化淀粉的制备

Preparation of modified plasticized starch under pre/co-irradiation

采用低剂量辐照技术对玉米淀粉进行改性处理,将预辐照、共辐照淀粉分别与己内酰胺、丙三醇按比例混合均匀,使用双螺杆挤出机进行混炼,经低温冷冻粉碎、索氏提取对萃取产物结晶度、分子结构和化学键、热力学性能、化学成分、亲疏水性等进行分析。结果表明:采用同一辐照剂量,不同辐照方式,淀粉与己内酰胺反应后,热稳定性均有所提高;己内酰胺成功接枝到玉米淀粉上,导致淀粉晶面发生改变,试样表面含氮量提高;水接触角增大,其中,共辐照接枝物水接触角达99.229°,疏水性大幅提升,并且拉伸强度达到8.3 MPa。

Corn starch was modified by low-dose irradiation technology.The pre-irradiated and coirradiated starch were mixed evenly respectively with caprolactam and propanetriol in proportion by the twin-screw extruder.The crystallinity,molecular structure and chemical bonds,thermodynamic properties,chemical composition,hydrophilicity and hydrophobicity of the extracted substances were characterized after low-temperature freeze crushing and Soxhlet extracting mixed starch.The results show that the thermal stability of starch reacted with caprolactam is improved with the same irradiation dose and different irradiation methods.Caprolactam is successfully grafted onto corn starch,resulting in the change of surface of starch crystal,the increase of nitrogen content on the surface and contact angle of samples.The contact angle of the co-irradiated graft reaches 99.229°,whose hydrophobicity is greatly improved,and whose tensile strength reaches 8.3 MPa.