Modified Densified Waste of Expanded Polystyrene and Its Blends With Polyamide 6

Abstract

The regularities of expanded polystyrene (EPS) waste modified by polyvinylpyrrolidone (PVP) with the simultaneous gas release in various solvents were revealed. The upper sorption limit depends on the nature of the solvent, the concentration and molecular mass of the PVP, the temperature of the process, and the apparent density of the EPS. It was established that the sorption limit of PVP increases with increasing of its concentration in the system and decreases with molecular mass increasing. Based on XRD and FTIR analyses, it was determined that materials based on polyamide 6 and EPS modified by PVP have an increased crystallinity degree by 10-15%, a smaller average crystallite size and higher technological compatibility. The addition of PVP-modified EPS contributes to the increase of the yield strength of polyamide 6 by about 5%-10%. The increase of the Vicat softening point by 5-8 K and the surface hardness by 25-30 MPa of materials based on polyamide 6 and modified polystyrene was investigated. It is caused by the redistribution of intermolecular bonds between the components of the blend under by the effect of a uniformly distributed PVP in the EPS resulting in increased compatibility between the components and the compacted structure. POLYM. ENG. SCI., 60:935-943, 2020. * modified EPS; ** degassed EPS. FIG. 7 XRD patterns of mixtures on the basis of PA-6 and EPS: (a) pure PA-6; (b) mixture of PA-6 and modified EPS; (c) mixture of PA-6 and degassed EPS. EPS content 5 wt%. 1-approximation curve of diffraction; 2, 3, 4, 5optimized curves of intensity of reflexes of the planes (200)α-, (002)α-, γ-, and amorphous phase.

Polystyrene carbon composite foam with enhanced insulation and fire retardancy for a sustainable future: Critical review

“…One of the major challenges of preparing graphite-polystyrene beads via suspension polymerization is preventing the separation of graphite from the polymerization solution. 94,95 Zhao et al 88 used a homogeneous dissolution reaction system to overcome the instability issue during suspension polymerization process. The agglomeration of graphite was avoided by using styrene monomer as a solvent to dissolve EPS and achieve better dispersion of graphite as the viscosity of the system increased.…”

Study on preparation of highly dispersed graphite composite expandable polystyrene foam by homogeneous dissolution‐suspension polymerization with waste polystyrene

“…In conventional suspension polymerization, the low compatibility of graphite with styrene monomer and its own agglomeration tendency prevent the homogeneous dispersion of graphite in the organic phase, resulting in instability of the polymerization process. [33][34][35][36][37] In suspension polymerization, the monomer and graphite are suspended as small droplets in the dispersion medium for polymerization. In small droplets, styrene monomer (0.909 g/cm 3 ) and graphite (2.09-2.33 g/cm 3 ) are subjected to different gravitational and centrifugal forces of rotation and revolution due to their different densities.…”