Modification of a poly(propylene-co-ethylene) copolymer by incorporation of zeolites for membranes with improved mechanical properties and gas and water permeability

In this work, a poly(propylene-ethylene) copolymer matrix (VMX) was melt blended with two zeolite types, 13X zeolite and NaY zeolite, respectively. The zeolite content ranged up to 100 phr for zeolite 13X and up to 80 phr for zeolite NaY. Defect-free films with homogeneous filler dispersion were obtained. No modification of the copolymer crystallinity degree was observed after filler adding. Both fillers led to an increase of the degradation temperature by 20°C with respect to the reference VMX film. Mechanical reinforcement was evidenced with an increase of the tensile modulus by a factor two going from the reference VNX film to the composites with the highest zeolite loadings. Additionally, the water permeability increased by more than two decades going from reference matrix to composites with 100 phr of 13X zeolite and 80 phr of NaY zeolite. Opposite effects were evidenced on gas permeability as a function of zeolite type. When 13X zeolite was incorporated into the matrix, O 2 permeability decreased from 1.5 barrer for the reference matrix to 1.1 barrer for the composite with a zeolite content of 100 phr. For the composite containing 80 phr NaY, a value of O 2 permeability of 4.8 barrer was obtained. The same trends were observed for CO 2 . Establishment of relation between structure and properties as well as exploitation of Maxwell and modified Maxwell models were made to explain the gas transport behaviour as a function of the zeolite type.