Effects of the metakaolin-based geopolymer on high-temperature performances of geopolymer/PVC composite materials

This paper described a method to fabricate high performance geopolymer/PVC composite materials at a low cost by adding metakaolin-based geopolymers to PVC. Mechanical performance test results demonstrated that the geopolymer/PVC composite materials had good mechanical properties compared with pure PVC when the geopolymer content was less than 10 mass%; the fracture strengths and tensile strengths of the geopolymer/PVC composite materials were increased compared to those of pure PVC, and the optimal geopolymer content was 4 mass%. The Vicat softening, thermogravimetric analysis, and differential scanning calorimetry results indicated that the Vicat softening temperatures of the geopolymer/PVC composite materials were increased by 2-6 degrees C compared with that of pure PVC. The thermal stabilities of the geopolymer/PVC composite materials were enhanced because the geopolymer inhibited and absorbed the HCl released from PVC due to the molecular chain defect structure of PVC. The thermal decomposition activation energy of the geopolymer/PVC composite with 4 mass% geopolymer content reached 274.78 J mol(-1), representing an 80.7% increase compared to that of pure PVC. Thus, the addition of geopolymer into PVC greatly improved the thermal stabilities of the composite materials and significantly reduced the fabrication cost for industrial applications. (C) 2015 Elsevier B.V. All rights reserved.