Properties and mechanism of polyvinyl alcohol composite films modified by MCC
Microcrystalline cellulose(MCC)was extracted from wheat straw,which was added to polyvinyl alcohol(PVA)for modification to prepare PVA/MCC composite membranes by blending and tape casting.The effect of NaOH concentration on the yield of cellulose and the effect of MCC content on mechanical properties and thermal properties of PVA composite membranes were investigated.The structure and micromorphology of the membranes were analyzed.The results show that the cellulose yield reaches the maximum of 53.9%when the mass fraction of NaOH is 4%.The thermal stability of the composite membranes is improved after adding MCC into PVA.The mechanical properties of the membranes first increase and then decrease with the increase of the amount of MCC.When the MCC content is 9%,the tensile strength and nominal strain at break of the composite films are the maximum,which are 191%and 636%higher than those of pure PVA.when the content of MCC is 12%,MCC agglomerates in PVA to form an obvious"island structure",resulting in the decline of mechanical properties of the composite membranes.
NETL
NSTL
万方数据
