Poly(vinyl chloride) Composites with Raspberry Pomace Filler

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Poly(vinyl chloride) (PVC) is a widely used polymer, but its applications can be limited by properties like thermal stability and flammability.
• Natural fillers offer a sustainable alternative to traditional additives, potentially improving material properties and reducing environmental impact.
• Raspberry pomace, a byproduct of fruit processing, contains valuable components that can be utilized as a filler.

Purpose of the Study:

• To investigate the effects of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure, and processability of poly(vinyl chloride) (PVC) composites.
• To assess the potential of raspberry pomace as a sustainable filler for enhancing the performance of PVC.
• To determine the optimal concentration of raspberry pomace for achieving desired material characteristics.

Main Methods:

• Chemical extraction of raspberry pomace to remove bio-oil, ensuring homogeneous composite formation.
• Incorporation of extracted raspberry pomace filler into a PVC matrix at various concentrations.
• Evaluation of thermal stability using thermal analysis techniques.
• Assessment of mechanical properties including tensile strength, impact strength, modulus of elasticity, and Shore hardness.
• Flammability testing according to the UL94 standard.
• Analysis of chemical structure and hydrogen chloride emission under fire conditions.

Main Results:

• Extraction of naphtha from raspberry pomace enabled the creation of homogeneous PVC composites.
• Addition of 20% raspberry pomace filler increased the thermal stability of PVC composites by approximately 30%.
• Composite density, impact strength, and tensile strength decreased with increasing filler content, while modulus of elasticity and Shore hardness increased.
• All tested PVC-raspberry pomace composites achieved a V0 flammability rating under the UL94 test.
• Composites with 20-40% filler exhibited reduced hydrogen chloride emission during fire exposure.

Conclusions:

• Chemically extracted raspberry pomace can be effectively used as a filler in PVC composites.
• The incorporation of raspberry pomace significantly enhances the thermal stability and flame retardancy of PVC.
• While mechanical properties like tensile and impact strength are reduced, the increased rigidity and hardness, coupled with excellent fire resistance, make these composites suitable for flame-resistant applications.
• The use of raspberry pomace offers a sustainable approach to developing high-performance, flame-resistant PVC materials with reduced environmental impact.