Sustainable Cotton Gin Waste/Polycaprolactone Bio-Plastic with Adjustable Biodegradation Rate: Scale-Up Production through Compression Moulding

Abstract

Cotton gin trash (CGT), a lignocellulosic waste generated during cotton fibre processing, has recently received significant attention for production of composite bio-plastics. However, earlier studies were limited to either with biodegradable polymers, through small-scale solution-casting method, or using industrially adaptable extrusion route, but with non-biodegradable polymers. In this study, a scale-up production of completely biodegradable CGT composite plastic film with adjustable biodegradation rate is proposed. First using a twin screw extruder, the prepared CGT powder was combined with polycaprolactone (PCL) to form pellets, and then using the compressing moulding, the pellets were transformed into bio-plastic composite films. Hydrophilic polyethylene glycol (PEG) was used as a plasticiser in the mixture and its impact on the biodegradation rate was analysed. The morphology of CGT bio-plastic composite films showed even distribution of CGT powder within the PCL matrix. The CGT incorporation improved the UV resistance, thermal stability, and Young’s modulus of PCL material. Further, the flexibility and mixing properties of the composites were improved by PEG. Overall, this study demonstrated a sustainable production method of CGT bio-plastic films using the whole CGT and without any waste residue produced, where the degradation of the produced composite films can be adjusted to minimise the environmental impact.

Biodegradable UV-Protective Composite Film from Cellulosic Waste: Utilisation of Cotton Gin Motes as Biocomponent

“…The FTIR spectra of GM powder, PCL film, PEG flakes and GM composite films are shown in Figure 5 . The O–H stretching vibration of around 3338 cm −1 corresponded to the lignocellulose structure in GM powder, which shifted to 3445 cm −1 for GM-50 and GM-40 composite films, possibly due to the establishment of hydrogen bonding between GM with the polymers, i.e., PCL and PEG [ 17 ]. The symmetric and asymmetric CH 2 stretching were seen in all the spectra at 2868 cm −1 and 2943 cm −1 , respectively.…”

“…However, the peak at 1375 cm −1 due to the phenolic OH group in lignin was seen in GM and the composite samples. The alcoholic C–O stretching was seen near 1240 cm −1 [ 17 ] in all the spectra of PEG, PCL and GM composite films. The C–O–C ether in PEG and PCL showed peaks around 1095 cm −1 and 1175 cm −1 , respectively [ 28 ].…”

“…This was proved by the band near 680 nm for both the bio-based composite films. This band was due to the presence of lignin in GM, which contains different chromophore groups, e.g., guaiacyl (for yellow-brown colour), syringyl (for red-purple colour) and aromatic rings [ 17 ]. The zero UV transmission of GM composite films from 400 nm to 200 nm was related to the presence of lignin in GM.…”

“…There is also an ongoing interest in using cotton ginning waste, such as gin trash in composite preparations with different polymers including polypropylene [ 15 ], polyvinyl alcohol [ 16 ] and polycaprolactone (PCL) [ 17 ]. However, GM requires separate attention in the composite preparation due to its significantly higher cellulose content than gin trash (30% cellulose) [ 13 ].…”

Tensile Properties of Natural Fibre-Reinforced FDM Filaments: A Short Review

“…Other than PLA, polycaprolactone (PCL) and polypropylene (PP) are also proposed for FDM where natural fillers were used. PCL is probably the fastest among the synthetic polymers that has a biodegradable profile [53]. Another advantage of PCL is its FDM processability at low temperatures (80-150 • C) [33] which is much lower than ABS and PLA (200-220 • C) [52], and is thus more energy-saving.…”