Open Access

ARTICLE

Preparation of Hollow-Porous Rosin-Based Polyurethane Microspheres with pH-Responsive Characteristics

Caili Yu, Hao Liu, Jintao Shao, Faai Zhang^*

College of Chemistry and Biology Engineering, Guilin University of Technology, Guilin, 541004, China

* Corresponding Author: Faai Zhang. Email:

(This article belongs to this Special Issue: Bio-based/Degradable Materials towards A Sustainable Future)

Journal of Renewable Materials 2022, 10(4), 1049-1061. https://doi.org/10.32604/jrm.2022.017315

Received 01 May 2021; Accepted 02 July 2021; Issue published 02 November 2021

Abstract

Preparation of polymer microspheres from naturally occurring resource is a challenge. Here, a rosin-based polyol (RAG) was used to prepare polyurethane resin (RPU) firstly, and then act as both self-assembled precursor and emulsifier, rosin based polyurethane microspheres (RPUMs) were prepared. In the process of self-emulsification, the RPU formed vesicles by self-assembly. The outer shell of the vesicle consisted of hydrophilic segments, while the inner shell contained the hydrophobic phase. After cross-linking the RPU and removal of the solvent in the core, the porous-hollow microspheres with pH-sensitive were obtained. The microspheres were characterized by optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The effect of type and amount of the hydrophilic chain extender, and solvent on the morphology, particle size and distribution, and buffer volume of the microspheres were determined. The best conditions for synthetic RPUMs were as follows: n_NCO/n_OH = 1, n_RAG:n_{1-(2-hydroxyethyl) piperazine} = 4:6, with azodiisobutyronitrile level of 1.0 wt.%, based on reactive monomers, mixing speed of both emulsification and polymerization at 400 r·min⁻¹, the RPUMs synthesized had porous-hollow structure with a buffer volume of 1.6 mL.

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