Preparation and evaluation of the poly(lactic acid)-cottonseed oil composite films

Authors: He, Zhongqi; Rogers, Stephen; Nam, Sunghyun; DHANDAPANI, RENUKA - Cotton, Inc

Submitted to: ACS Omega
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2026
Publication Date: 2/10/2026
Citation: He, Z., Rogers, S.I., Nam, S., Dhandapani, R. 2026. Preparation and evaluation of the poly(lactic acid)-cottonseed oil composite films. ACS Omega. 11(7): pg 12675-12686. https://doi.org/10.1021/acsomega.5c13060?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as.
DOI: https://doi.org/10.1021/acsomega.5c13060?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as

Interpretive Summary: The growing severity of plastic waste problems has positioned agricultural-based materials as promising alternatives with significant potential for future growth. Thus, i t would be useful to offer cottonseed byproduct as a viable entry into this new opportunity. Thus, we hypothesize that cottonseed oil (CSO) can be an effective reinforcing (plasticizer) agent to improve the properties of poly(lactic) acid (PLA)-based biocomposite products. For this purpose, in this work, we 1) tested the composite making with different PLA: CSO ratios to find the applicable formulation range, 2) measured selected properties of PLA-CSO composites and evaluated their feasibility as potential products, and 3) applied advanced instrumental analysis to explore the morphological features and chemical interactions between PLA and CSO in the film formation. Our data demonstrated that CSO could serve for green chemistry applications as a renewable biomass material to make PLA composites. Furthermore, no apparent differences in performance between the composite films made from crude CSO and commercial refined CSO implied that CSO from various sources and/or quality (e.g., low quality, or recycled oil products) can be used for the PLA-CSO composite making for a variety of application purposes.

Technical Abstract: Poly(lactic) acid (PLA)-agricultural biomass composites have been considered as renewable bioplastics with various industrial application potentials. In this work, PLA-cottonseed oil (CSO) composite films were made by solvent casting with 5 to 30 parts of refined and crude CSO per 100 parts of resin (phr) with a neat PLA film control (PC0). No apparent impacts of the CSO type on the measured parameters of these PLA-CSO films were observed, indicating that a wide range of CSO from various sources and/or grades could be used for the PLA-CSO film manufacturing. All films were colorless, although the opacity slightly decreased with higher oil content. The tensile strength of these films decreased steadily from 169 MPa (PC0) to around 20-30 MPa in 30-phr films. On the other hand, the flexibility (elongation at break) of the composite films significantly (p = 0.05) improved by 46% to 230%, compared to that of PC0. Incorporating CSO into the PLA matrix increased the water vapor permeability, while the plasticizer migration seemed not to be of great concern. The data obtained indicate that these PLA-CSO formulations give balanced mechanical performance and flexibility suitable for food packaging applications. The scanning electron microscopy coupled with energy-dispersion X-ray spectroscopy revealed a smooth surface characteristic with an “CSO-rich islands & PLA-matrix sea” morphology in the PLA-CSO film samples. Fourier transform infrared spectroscopy further confirmed that molecular interaction between PLA and CSO occurred during the composite film formulation perhaps through the structure crosslinking and surface shielding of CSO by PLA.