Effect of Die Head Temperature at Compounding Stage on the Degradation of Linear Low Density Polyethylene/Plastic Film Waste Blends after Accelerated Weathering

Abstract

Accelerated weathering test was performed on blends of linear low density polyethylene (LLDPE) and plastic film waste constituting the following percentages of polyolefin polymers (wt.%): LLDPE (46%), low density polyethylene (LDPE, 51%), high density polyethylene (HDPE, 1%), and polypropylene (PP, 2%). Compounded blends were evaluated for their mechanical and physical (optical) properties. The impact of photodegradation on the formulated blends was studied, and loss of mechanical integrity was apparent with respect to both the exposure duration to weathering and waste content. The effect of processing conditions, namely, the die head temperature (DHT) of the blown-film assembly used, was investigated in this work. It was witnessed that surpassing the melting point of the blends constituting polymers did not always result in a synergistic behaviour between polymers. This was suspected to be due to the loss of amorphous region that polyolefin polymers get subjected to with UV exposure under weathering conditions and the effect of the plastic waste constituents. The total change in colour (ΔE) did not change with respect to DHT or waste content due to rapid change degradation on the material’s surface. Haze (%) and light transmission (%) decreased with the increase in waste content which was attributed to lack of miscibility between constituting polymers.

On the Kinetics of Degradation Reaction Determined Post Accelerated Weathering of Polyolefin Plastic Waste Blends

“…It is also worth mentioning that various implications, touching base on sustainability and plastic waste pollution, fall within the framework of this study. The developed film blends originating from PSW, have proven their viability as a standalone produce comparable to ones on the market [33,34,54]. This also supports the claim that freshly discarded PSW with somewhat preserved integrity, allows the development of plastic film blends with acceptable market standards.…”

“…The material was segregated and cleaned for further processing [33]. The PSW contained the following polymer as constituting elements (by wt%): LLDPE (46%), LDPE (51%), HDPE (1%); and PP (2%) [34]. The PSW was milled to 3 mm flakes using a Tecnova cutting mill and pelletized to 3 mm pellets using a Tecnova single screw extruder (L/D = 30) at 40 bars pressure and 70 rpm.…”

“…The PSW was milled to 3 mm flakes using a Tecnova cutting mill and pelletized to 3 mm pellets using a Tecnova single screw extruder (L/D = 30) at 40 bars pressure and 70 rpm. The cooling water temperature was maintained between 16 and 17 °C [12,33,34]. The recycling procedure aimed at dry blending (without the addition of additives) LLDPE with the PSW in different weight ratios.…”

Compounding and Processing Hydro-Biodegradable Plastic Films for Plastic Waste Reduction. Part I: Processing Conditions and Environmental Performance Against Plastic Solid Waste

“…In general, lightness (L*) was in line with the general colour measurement theory, since transparent and achromatic films should have high lightness and minimum colour space values of a * and b*. Al-Salem et al [27], [28] also tested colour parameters of control unexposed LLDPE/Waste (100/0) sample extruded using a single screw extruder (L/D=30) and film blowing machine. The reported L*, a* and b* values were 29.0, -0.4, and -3.5, respectively.…”

Mechanical Profiling of Commercial Grade Biodegradable Plastic Films Post Exposure to Natural and Accelerated Weathering

“…The equipment used was cleaned every 800 h to remove scale deposits resulting from water evaporation during the condensation cycles. Readers are referred to Al-Salem et al [7], [8], [14] for a detailed depiction on the accelerated weathering procedure.…”