Green composites based on polypropylene matrix and hydrophobized spend coffee ground (SCG) powder

Abstract

Green composites were prepared with polypropylene matrix and 20 wt.% spent coffee ground (SCG) powder for uses as a wood plastic composite (WPC). The effects of hydrophobic treatment with palmitoyl chloride on SCG powder is compared with conventional surface treatment based on silanization with (3-glycidyloxypropyl) trimethoxysilane and the use of a maleated copolymer compatibilizer (polypropylene-graft-maleic anhydride, PP-g-MA) in terms of mechanical properties, morphology, thermal properties and water uptake. Composites were previously mixed in a twin-screw co-rotating extruder and subsequently subjected to injection moulding. The comparative effect of the different surface treatments and or compatibilizers on mechanical performance was studied by flexural, impact tests and dynamic mechanical thermal analysis (DMTA-torsion); in addition, the stabilizing effect of SCG was revealed by differential scanning calorimetry (DSC) and thermogravymetric analysis (TGA). As one of the main drawbacks of wood plastic composites and natural fiber reinforced plastics is the moisture gain, water uptake tests were carried out in order to quantify the effectiveness of the hydrophobization process with palmitoyl chloride. Results show a slight increase in flexural modulus for composites with both untreated and treated/compatibilized SCG powder (20 wt.%).As expected, thermal stability is improved as indicated by an increase of more than 8% in the

Mechanical, dynamic mechanical and morphological properties of composites based on recycled polystyrene filled with wood flour wastes

“…So, more energy for debonding and fiber pull-out is required and the composite impact strength increases (Nygård et al 2008). García-García and coworkers also observed an improvement in the impact strength after the addition of polypropylene grafted maleic anhydride in composites of polypropylene reinforced by coffee ground powder (García-García et al 2015). The authors attribute this improvement to the strong interactions among particle-polymer at the interface.…”

Characterization of Wastes and Coproducts from the Coffee Industry for Composite Material Production

“…In recent years, there have only been a handful of published studies in this area. These have mostly focused on SCG biocomposites with polymers including poly(lactic acid) (Baek et al 2013;Lee et al 2015a;Wu 2015), polypropylene (Jaya Chitra et al 2014;García-García et al 2015), recycled high-density polyethylene (Cestari et al 2013), and poly(vinyl alcohol) (Lee et al 2015b). After extensive research, only one publication on CC composites, with feather keratin polymer, was found (Barone 2009).…”

Development and characterization of green composites from bio‐based polyethylene and peanut shell

“…Firstly, polyethylene or polypropylene fraction in PE-g-MA and PP-g-MA respectively 4 can interact with some polymer chains due to chemical affinity while maleic anhydride groups in the compatibilizer structure can react with hydroxyl groups in ligno-cellulosic particle by an esterification reaction to give increased matrix-filler interactions which have a positive effect on particle dispersion and stiffness. 13,18 Despite this, ductile properties are not usually improved due to the brittleness that the filler provides because of presence of particle aggregates and matrix discontinuity, which promote stress concentration phenomena.…”

“…This fact, together with the problems related to petroleum depletion has led to a breakthrough in the field of environmentally friendly materials development; much of this progress has been observed in the field of polymer composites, mainly on natural fiber reinforced plastics (NFRP) and wood plastic composites (WPC) for everyday applications. [1][2][3][4] The use of natural fillers into a polymeric matrix provides attracting advantages such as reduced costs, lightness, excellent balanced mechanical properties, etc. together with a marked low environmental impact.…”