Lightweight polyethylene‐hollow glass microspheres composites for rotational molding technology

Abstract

Innovative composites based on polyethylene (PE) filled with hollow glass microspheres (HGMs) were formulated and successfully prepared as suitable plastic materials for rotational molding technology. The HGMs here used allow to attain lightweight materials with a reduced resin content and appealing aesthetical qualities. To enhance filler dispersion and phase adhesion, thus improving the ultimate properties of the composite materials, two compatibilization strategies were adopted: namely, surface modification of HGMs by dodecyl(triethoxy)silane or addition during mixing of a maleinized PE as insitu coupling agent. The effectiveness of the surface treatments on HGMs was assessed by attenuated total reflectance Fourier-transform infrared spectroscopy and thermogravimetric analysis investigations. PE-based composites at various HGMs contents (5, 10, and 20 wt%) were prepared by melt blending. Morphology of untreated and modified HGMs, their dispersion in the composites as well as filler/matrix adhesion were investigated by SEM microscopy. Thermal, rheological and mechanical properties of the composites were studied in comparison with neat PE. Rotational molding tests carried out both in laboratory and industrial site demonstrated the feasibility of producing lightweight plastic items (weight reduction up to 17%) of excellent aesthetics on a large scale.

Recent Developments in Inorganic Composites in Rotational Molding

“…These same authors later used glass fiber dust, a residue from wires insulation, into an LDPE matrix at 20% loading, blending both materials in a high-speed mixer to reduce the thermal degradation from the molten compounding, obtaining moderate increases in mechanical properties, even in impact strength [ 19 ]. Glass particles have also been proposed as reinforcement of PE in up to 20% [ 30 ]; this research highlights the importance of using a coupling agent, such as maleic anhydride grafted polyethylene, to improve interfacial bonding and ultimately the composite’s performance. The addition of such a compound results in higher increases in elastic modulus and avoids the decrease in tensile strength observed for composites without that compound.…”

“…They have found that the treatment of the glass particles is needed to increase the tensile modulus of composites and to avoid a reduction in tensile strength. The surface treatment proposed by these authors consisted of a first step of hydroxylation with NaOH, followed by a later silanization, as also presented by Stagnaro for PE-based composites [ 30 ].…”

Uniaxial Rotational Molding of Bio-Based Low-Density Polyethylene Filled with Black Tea Waste

“…The uniaxial rotational molding for this material can be successfully conducted [ 8 ]. Since the preparation of composite materials in rotational molding technology is receiving increased interest [ 1 , 9 , 10 ], the works discussing possibilities of preparing those composites in uniaxial rotational molding also increase. One of these kinds of works discusses the production of PE composites filled with hollow glass microspheres (HGM) [ 10 ], and another paper concerns the same filler but in a different polymeric matrix, mainly poly(caprolactone) (PCL) [ 11 ].…”

“…Since the preparation of composite materials in rotational molding technology is receiving increased interest [ 1 , 9 , 10 ], the works discussing possibilities of preparing those composites in uniaxial rotational molding also increase. One of these kinds of works discusses the production of PE composites filled with hollow glass microspheres (HGM) [ 10 ], and another paper concerns the same filler but in a different polymeric matrix, mainly poly(caprolactone) (PCL) [ 11 ]. In both these studies, fillers were submitted to a surface treatment, which was a two-step process; firstly, HGM particles were hydroxylated and then silanized to increase the adhesion between the polymer matrix and filler.…”

Crystallization Behavior of Poly(ε-Caprolactone)-Hollow Glass Microspheres Composites for Rotational Molding Technology

“…Thus, crystallization, occurring during the cooling step, is of great importance for the morphology and the resulting properties of the final product. Several studies were focused on polyethylene-based materials in order to investigate crystallization during the RM process [ 4 , 5 , 6 , 7 ] and the final properties of the rotomolded composites [ 8 , 9 , 10 , 11 , 12 , 13 ]. However, the recent growing interest for RM aimed to investigate the crystallization behavior of other polymers such as polypropylene [ 14 , 15 ], polyamide [ 16 ], and polylactide [ 17 , 18 ] for application in this technology process.…”