Beeswax as a natural alternative to synthetic waxes for fabrication of PLA/diatomaceous earth composites

Abstract

In this study, injection moulding was applied to produce biocomposites consisting of polylactide (PLA) and amorphous diatomaceous earth used as a filler at different concentrations. Natural wax and synthetic wax were added to improve processing properties, comparing the resulting biocomposites. The use of natural beeswax makes the composite environmentally friendly. The prepared composites contained 2.5, 5, 10 and 15% w/w filler. The test samples have been injection moulded. Rheological, mechanical, surface and other properties were assessed for the fabricated composites. The testing has shown that the use of wax additives has a significant influence on the mechanical properties (tensile strength, flexural strength, impact strength) and the hydrophilicity/hydrophobicity of composite surfaces. The addition of natural wax, especially at lower concentration, has a positive effect on the rheological properties of composites (melt flow rate, MFR), flexural modulus and impact strength. Different composite parameters are modified by different wax types so both natural and synthetic waxes, can be used interchangeably, depending on the required final material characteristics.

Bio-Based White Eggshell as a Value-Added Filler in Poly(Lactic Acid) Composites

“…Figure 5 illustrates the impact strength with filler loading for PLA composites containing ILS and WE fillers for two particles sizes of 63 µm and 32 µm. The pure PLA (e.g., the 4043D that was injection molded in this study) samples had an impact strength of 17.3 kJ•m −2 , which is in line with the literature impact strengths (un-notched Charpy) for PLA being between 19 kJ•m −2 [37] and 25 kJ•m −2 [15]. PLA composites in loadings of 5, 10, and 20 wt.% reduced in impact strength for composites containing 63 µm ILS fillers by 24%, 36%, and 41%, respectively, while 63 µm WE fillers were lowered by 49%, 53%, and 57%, respectively.…”

The Influence of Environmental Factors on the Degradation of PLA/Diatomaceous Earth Composites

“…The decrease in mechanical strength is related to the degradation of neat PLA present in each analyzed system and comparable for most systems; however, the lowest is for composites with synthetic wax in combination with the silanized filler, indicating the greatest stability of the systems, probably due to the combined effects of the presence of a well-dispersed filler as a UV blocker and hydrophobic wax stopping the composite from moisture diffusion. On the other hand, the mentioned systems provided the poorest mechanical properties as received, showing the limited compatibility of synthetic wax with the remaining components, especially the PLA matrix, as proven by the previous study [ 29 ]. Moreover, the polymer degradation occurs mostly in the near-surface region, which is further explained in the following sections (see Section 3.2 and Section 3.4 ).…”

Thermal and Sound Insulation Properties of Organic Biocomposite Mixtures

“…The advantage of using beeswax and fir resin as the matrix could be their improved compatibility with the filler, as they contain a wide range of compounds in their structure, including hydrocarbons with a chain length of C27-C33, free fatty acids with a chain length of C24-C32, and fatty acid esters in the case of beeswax [ 10 ] and terpenes and rosin acids in the case of fir resin [ 10 ], as well as other compounds. Also, among the advantages, the easy processing may be mentioned (due to their relatively lower melting/softening points compared to synthetic thermoplastics, for example).…”