Knowledge Bank

Plastic waste is an environmental concern that affects all forms of life, specifically marine life facing harmful effects of plastic pollution. Current industry trends lean towards the future production of bioplastics. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a promising bioplastic because of its compostability in defined conditions as well as its unique thermo-mechanical properties. Food and Agro-industrial waste are other environmental concerns that have increasing attention. Specifically, spent coffee grounds (SCG) emit methane into the atmosphere, a greenhouse gas 25x more potent than CO2. Many of these food wastes can be used as bio-fillers to increase the strengths of current bioplastics such as PHBV. The creation of a feasible PHBV SCG Fiber Composite would prove useful for greenhouse planter pot production because these pots need to be sturdy and retain water. The study will serve to characterize different PHBV SCG Composites. It was hypothesized that there is an optimum level of SCG and other defined additives that will yield a fiber composite with desirable mechanical, thermal, and water absorption properties. There were eight samples comprised of: PHBV pellets and 10/20/30 % of SCG per volume as well as samples with 10% SCG + additives [Peroxide(P), Coagent(C), Liquid Chain Extender(I), and Solid Chain Extender(II)]. Each sample underwent thermal, and mechanical testing and moisture absorption/water loss testing. Statistical analyses was performed to indicate the best mixture for a PHBV SCG composite and verify its feasibility. Results indicated that increasing amounts of SCG to the sample increased the crystallinity. The sample with 30% SCG had a crystallinity of 58.7% while the control PHBV had a crystallinity of 59.6%, suggesting that samples with SCG added had comparable stability. Adding SCG to the samples had a slight increase of water loss (~0.3%) suggesting they can retain water. Lastly, PHBV/SCG10/P, PHBV/SCG10/P/C, and PHBV/SCG10/P/C/S had significantly lower tensile stress values. Using SCG as a fiber composite would prove useful in the greenhouse planter pot industry since these pots need to be flexible and capable of maintaining soil moisture levels.