Abstract:

Polyvinyl chloride (PVC) foam board is prepared by extrusion foaming of PVC with low polymerization degree, and the PVC foam board is prone to curling movement along the force direction of the molecular chain due to environmental changes, resulting in shrinkage and deformation of the board. Heavy calcium carbonate (HCC) was used as raw material, polyvinyl alcohol (PVA) and tannic acid (TA) were used as modifiers to prepare modified HCC. It was combined with PVC to prepare PVC foam sheets. Infrared spectrometer, differential scanning calorimeter, scanning electron microscope, Vicat softening point tester and universal electronic stretching machine were used to characterize the foamed board, and the effect of modifier dosage on the dimensional stability of the foamed board was discussed. The results show that when the TA content is 3% of HCC, the glass transition temperature of PVC foam board is 88.1 ℃, the temperature of Vicat softening point is 75.21 ℃, and the PVC foam board has excellent dimensional stability, and the cell structure is stable and uniform, and has the best tensile strength of 6.17 MPa. Modified HCC particles have good dispersion, strong binding ability with PVC, and high dimensional stability of PVC foam board can replace the use of wood in home decoration boards, which is of great significance to protect the environment.

Key words: polyvinyl chloride, extrusion foaming, filler modification, dimensional stability, hydrogen bond self-assembly