Nanocellulose-Based Thermoplastic Polyurethane Biocomposites with Shape Memory Effect

Abstract

In 2020, we published a review on the study of semi-crystalline thermoplastic polyurethane elastomers and composites based on the shape memory effect. The shape recovery ability of such polymers is determined by their sensitivity to temperature, moisture, and magnetic or electric fields, which in turn are dependent on the chemical properties and composition of the matrix and the nanofiller. Nanocellulose is a type of nanomaterial with high strength, high specific surface area and high surface energy. Additionally, it is nontoxic, biocompatible, environmentally friendly, and can be extracted from biomass resources. Thanks to these properties, nanocellulose can be used to enhance the mechanical properties of polymer matrices with shape memory effect and as a switching element of shape memory. This review discusses the methods for producing and properties of nanocellulose-based thermo-, moisture-, and pH-sensitive polyurethane composites. The synergistic effect of nanocellulose and carbon nanofillers and possible applications of nanocellulose-based thermoplastic polyurethane biocomposites with shape memory effect are discussed. A brief description of nanocellulose terminology is also given, along with the structure of shape memory thermoplastic polyurethanes. There is significant interest in such materials for three primary reasons: the possibility of creating a new generation of biomaterials, improving the environmental friendliness of existing materials, and exploiting the natural renewability of cellulose sources.

Effects of cellulose micro and nanocrystals on the mechanical, thermal, morphological, and structural properties of rigid polyurethanes

“…3, both the flexural strength and flexural modulus for all the rPU composites significantly increased. However, the flexure strength slightly decreased for 0.25% MCC due to the possible aggregation of the MCC particles, as determined by Gorbunova et al (2023). The maximum and minimum increasing percentages in the flexural strength were determined as 47.1% for the rPU composites with 1% and 15.5% CNC for the PU composites with 0.25% MCC, respectively.…”

“…The addition of the fillers ranging from 0.25% to 1% generally increased both TS and TM. The TS was determined to improve at a range from 2.8% (18.3 MPa in rPU composites with 0.25% CNC) to 81.5% (32.3 MPa in rPU composites with 1% CNC) with the presence of the fillers due to better compatibility between CNC and the PU matrix as presented by Gorbunova et al (2023). The TM of the rPU composites was higher than neat rPU, and the maximum tensile modulus was found as 1.1 GPa (an improvement of 37.5%) for the PU composites with 0.25% MCC, 0.5% CNC, and 1% CNC.…”

Advances in Graphene‐Reinforced Polyurethane Nanocomposites: An Advanced Shape Memory Material

“…The choice of diisocyanates and diols depends on the desired properties of the SMPU, such as the transition temperature, mechanical properties, and biocompatibility. [88,89] The polymerization of SMPUs usually involves a two-step process known as step-growth polymerization or polyaddition reaction. [90,91] In the initial step, diisocyanates and diols are mixed in a stoichiometric ratio with certain reaction conditions and form a prepolymer.…”

“…SMPUs are typically composed of two main types of monomers: diisocyanates and diols. The choice of diisocyanates and diols depends on the desired properties of the SMPU, such as the transition temperature, mechanical properties, and biocompatibility [88,89] . The polymerization of SMPUs usually involves a two‐step process known as step‐growth polymerization or polyaddition reaction [90,91] .…”

Multifunctional Polymeric Nanocomposites for Sensing Applications—Design, Features, and Technical Advancements

“…Ding et al [104] developed thermoplastic polyurethane, hydroxyethyl cotton cellulose nanofibers, and carbon nanotube-derived nanocomposite as strain sensors. Figure 7 shows the formation route of the nanocomposite [105,106]. For carbon nanotube and hydroxyethyl cotton cellulose nanofiber nanofillers, a freeze-drying method was used [107,108], whereas the solution procedure and curing approaches were applied to form nanocomposites.…”