Cellulose and/or lignin in fiber-aligned electrospun PET mats: the influence on materials end-properties

Cellulose, combined with lignin in some instances, was used to prepare mats made of fibers preferentially oriented in one direction. The aim of this study was evaluating the influence of this polysaccharide on the end properties of the mats when a thermoplastic polymer (in this case recycled polyethylene terephthalate; PET) is used as the primary component of solutions subjected to electrospinning. All of the prepared mats were composed mostly of ultrathin fibers. The mechanical properties were evaluated in the preferred and perpendicular directions of the alignment of the fibers. The storage and elastic moduli, as well as the tensile strength, were higher in the preferred direction. Cellulose led to mats with higher T_g PET values, indicating interactions at the molecular level between the chain segments of both polymers. One of the cellulose mats, (PETC-2), showed a superior alignment index (AI = 0.72 ± 0.03) and a higher average preferred orientation (APO = 88 ± 1°), which, in turn, led to higher mechanical properties, storage modulus, tensile strength, and elastic modulus when evaluated in the preferred direction of fiber alignment (PETC-2 dir), compared to the others. The results reveal that cellulose can be used to tune various properties of mats based on thermoplastics, thereby significantly increasing the range of applications of these materials.