The influence of flame retardant filler on the mechanical, thermal, rheological and flame retardancy properties of silane crosslinked linear low density polyethylene/low density polyethylene blend nanocomposite

Abstract

Linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) blend at 70/30 wt% ratio respectively was grafted and crosslinked with aluminum hydroxide (ATH) with and without the presence of montmorillonite (MMT) nanoclay using twin screw extruder. The effect of flame retardant ATH loading (5, 10, 15, 20 wt%), with and without the addition of MMT nanoclay, on the mechanical, thermal, rheological, flame retardancy and morphological properties has been studied and reported. The incorporation of ATH filler into crosslinked LLDPE/LDPE blend enhanced all the aforementioned properties; and it was found that increasing ATH content from zero to 20 wt% has improved tensile strength of the virgin LLDPE/LDPE blend by about 16 MPa. However, the addition of MMT nanoclay into the crosslinked LLDPE/LDPE blend with ATH filler, particularly at higher ATH loading (20 wt%), has not significantly increased the tensile strength. Thermogravimetric analysis (TGA) results have shown significant thermal stability improvement for virgin LLDPE/LDPE blend due to crosslinking, increased ATH filler loading, and subsequent addition of MMT nanoclay. However, at onset temperature, lower degradation rate was observed for samples containing higher ATH loading (15 and 20 wt%). At lower frequency region, it was found that the incorporation of higher ATH filler content and MMT nanoclay into crosslinked LLDPE/ LDPE blend have increased the complex viscosity, storage modulus and loss modulus for virgin LLDPE/LDPE. The FTIR results have confirmed that silane crosslinking reaction of the virgin LLDPE/LDPE blend has occurred. The results obtained from flammability test, UL-94 tests, showed that the flame retardancy of virgin LLDPE/LDPE blend has improved significantly due to the higher ATH filler loading, with and without the presence of MMT nanoclay filler. It was found that the higher ATH filler loading (20 wt%), addition of MMT nanoclay and subsequent crosslinking in the virgin LLDPE/LDPE blend have exhibited and achieved the best flame retardancy result for virgin LLDPE/LDPE blend. Furthermore, SEM results have also shown that

Effect of magnesium hydroxide and graphene nanoplatelets on the properties of peroxide cross‐linked linear low‐density polyethylene nanocomposite

“…Additionally, this behavior of thermal result improvement for neat LLDPE could be described clearly the significance of the cross-linked network formation in the LLDPE matrix by peroxide cross-linking, which slows down the mass loss in the cross-linked LLDPE matrix during the combustion process, and finally, vitalizes the creation of a dense char layer on the sample surface. However, the previously reported work 40 for silane crosslinked PE blend with ATH and MMT nanoclay has achieved lower maximum decomposition temperature compared to higher decomposition temperature in this study. This indicates that use of peroxide cross-linking, MAH as a flame retardant filler, and GNP have better combined effect to achieve higher thermal stability for neat LLDPE.…”

“…A vertical laboratory UL-94 burning test was performed as stated by ASTM D 3801 testing technique, 45 and detailed experimental testing procedure was conducted according to the previously reported process. 40 For example, if tested sample scorches up to maximum 60 s and no burning drops is shown by the sample, it is classified as V-0; similarly if it burns up to 30 s and no dripping occurs, it is categorized as V-1. It is graded as V-2 if burning droplets happen with no total consumption of the sample within 30 s of burning time.…”

Improvement of flame retardancy and thermal stability of highly loaded low density polyethylene/magnesium hydroxide composites

“…The observed deterioration in both properties occurred due to the incompatibility between the additives and the LDPE matrix leading to the heterogeneous distribution of both MH and MC and the formation of agglomerated particles at this high additive content 26 . The agglomerates of varying sizes, as can be seen in SEM images (Figure 3), create stress centres, and also the presence of an extensive additive amount decreases the free volume in composite structure and thus restricts the mobility of LDPE chains, resulting in a decrease in tensile strength as well as elongation at break values 55 …”

“…26 The agglomerates of varying sizes, as can be seen in SEM images (Figure 3), create stress centres, and also the presence of an extensive additive amount decreases the free volume in composite structure and thus restricts the mobility of LDPE chains, resulting in a decrease in tensile strength as well as elongation at break values. 55 On the other hand, for LDPE-5 composite with 40 wt % MC, the tensile strength value was improved to 8.64 MPa, while no notable change was seen at elongation at break value. This enhancement in tensile strength can be due to the better interfacial interaction between MC and the LDPE chains at this optimum additive combination, resulting in better dispersion of MC in the polymer matrix.…”

Developing an in-Line method to improve mechanical and flame retardancy performance of polyethylene fiber

“…18 The studies based on polyethylene fiber flammability have limited sources because PE flammability is performed using PE composites or molds rather than PE fibers as test specimens. [23][24][25][26][27] Fredi et al 23 used fumed nanosilica with micro-sized ATH and Mg (OH) 2) for LLDPE in different concentrations. Samples were hot-pressed to produce test specimens and the best results were obtained in samples called PE-HF-20 (%)-fume nanosilica-5 (%).…”