磺化聚醚醚酮/聚乙烯复合膜的制备及对生菜的贮藏保鲜

Preparation of SPEEK/PE Composite Membrane and Application in Lettuce Preservation

以磺化聚醚醚酮(SPEEK)为涂层,聚乙烯(PE)为基底,制备了自发式气体调节SPEEK/PE复合膜,研究不同磺化度SPEEK对SPEEK/PE复合膜的透气性、透湿性、防雾性能等气调特性的影响,并将SPEEK/PE复合膜应用于生菜的气调气调保藏。结果表明,与SPEEK膜相比,不同磺化度SPEEK/PE气调复合膜对CO2和O2的透气系数均有轻微下降,SPEEK/PE复合膜对CO2/O2的分离系数从0.73增加到5.58。不同磺化度的SPEEK/PE复合膜对水蒸气的透过系数在1.50×10^-14~4.00×10^-14 g·cm/(cm·s·Pa)之间,与SPEEK膜2.00×10^-12~2.46×10^-12 g·cm/(cm·s·Pa)相比,水蒸气透过系数下降两个数量级,且SPEEK/PE复合膜具有良好的防雾性能。高磺化度SPEEK/PE复合膜对生菜具有良好的气调保藏效果,与空白对照和PE膜组相比,保藏20 d后生菜失重率分别降低92.25%、22.06%,叶绿素损失分别减少85.00%、50.00%,总酚含量下降分别减少73.97%、26.98%,维生素C含量损失分别降低50.00%、31.48%,可溶性固形物含量下降分别减少67.21%、21.31%。4℃时SPEEK/PE复合膜能将生菜保藏环境中的CO2和O2含量分别维持在10.00%~12.00%和4.00%~5.00%,并将生菜保藏期期延长到20 d。

Spontaneous gas-regulated sulfonated polyetheretherketone(SPEEK)/polyethylene(PE)composite membranes were prepared.The effect of SPEEK with different sulfonation degree on gas permeability,moisture permeability and anti-fog properties of SPEEK/PE composite membranes were studied by a series of testing methods.Then,the SPEEK/PE composite membranes ware applied to preserve lettuce.The results showed that the permeability coefficient of different sulfonation degree of SPEEK/PE modified membranes for CO2 and O2 decreased slightly.The separation coefficient of SPEEK/PE composite membrane for CO2/O2 increased from 0.73 to 5.58.The moisture permeability of composite membrane was between 1.50×10^-14~4.00×10^-14 g·cm/(cm·s·Pa),which reduced by two orders of magnitude,compared to SPEEK membrane(between 2.00×10^-12~2.46×10^-12 g·cm/(cm·s·Pa).And the SPEEK/PE composite membran had good properties of anti-fog.The results of preservation experiment indicated that high sulfonation degree of SPEEK/PE composite membrane had good air-conditioning preservation effect on lettuce.Compared to ordinary PE group and blank group,the changes of the weight loss rate,chlorophyll content,total phenolic content,vitamin C content and soluble solid content of lettuce were reduced during the preservation process,and the preservation periods of composite membrane groups were extended by 12 days and 4 days respectively.Based on the preservation effect,at 4℃,SPEEK/PE composite film could maintain the content of CO2 and O2 in the packaging environment at 10.00%~12.00%and 4.00%~5.00%respectively,and extend the storage period of lettuce to 20 days.