@article{A. Madbouly_2022, title={Bio-based castor oil and lignin sulphonate: aqueous dispersions and shape-memory films }, volume={1}, url={https://eaapublishing.org/journals/index.php/bph/article/view/136}, DOI={10.37819/bph.001.02.0136}, abstractNote={<p>Aqueous polyurethane dispersions based on castor oil and lignin sulphonate (LS) were successfully synthesized in homogenous solution with nanoscale PU-lignin particle sizes as small as 35 nm. The particles size was found to be LS independent, while the dispersion viscosity increases dramatically with increasing the LS content. The increase in viscosity with increasing LS content was explained based on the chemical structure of LS. The LS is a water-soluble material and chemically reacted with diisocyanate to become a part of the dispersion particle (i.e., the nanoparticles is in fact a mixture or copolymer of castor oil-based polyurethane and lignin dispersed in water). The affinity of the PU-LS nanoparticle towards water could be increased with increasing the content of LS. Therefore, the PU-LS nanoparticle can adsorb thick water layer with increasing the LS content. According to thisĀ  suggestion, the free water in the dispersion would significantly decrease and consequently the dispersion viscosity increases considerably. The cross-link density was also increased with increasing the LS content of the thin films obtained from dispersion cast. The PU-LS thin films obtained from dispersion cast showed an excellent shape-memory effect and the shape recovery was found to be strongly LS dependent. Furthermore, the supper critical CO<sub>2</sub> solution was used successfully to create three-dimensional porous structure of PU-LS with cell size depends on LS content. The temporary folded shape of PU-LS with 5 wt.% LS changed to its permanent shape (plane stripe) within just 17 s once the sample was immersed in a water bath at the programing temperature.</p>}, number={2}, journal={ Biomaterials and Polymers Horizon}, author={A. Madbouly, Samy}, year={2022}, month={May} }