Date of Publication

6-2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemical Engineering

Subject Categories

Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Adviser

Arnel B. Beltran
Ying-Ling Liu

Defense Panel Chair

Michael Angelo B. Promentilla

Defense Panel Member

Nathaniel P. Dugos
Liza B. Patacsil
Marissa A. Pagcalinawan
Joey D. Ocon

Abstract/Summary

Recent development in the synthesis of sulfur copolymers (SDIB) via inverse vulcanization of elemental sulfur (S8) introduced a new sulfur-rich polymeric material but also provided a solution to the excess sulfur problem. SDIB as a new sulfur-containing polymeric material had overcome the limitation of processability by controlling comonomer ratios of S8 with 1,3-disisopropenlybenzene (DIB). However, limited research has been done to process SDIB in material development for more advanced application. Copolymerization of S8 and DIB resulted to structure-property relationship with high content of S-S bonds which enabled SDIB to have useful properties compared to other sulfur-containing polymers. Taking advantage of sulfur groups in polymer blending and electrospinning processes using varying concentrations of SDIB (5 and 10 wt%) combined with constituent polymer, PBz (10 wt%) was carried out in producing nanofiber material. Simple solution processing produced miscible blend using appropriate mixing approach due to the nature of copolymers-polymer interaction. Subsequent processing of SDIB/PBz blend through electrospinning was achieved by tailoring applied voltage with the polymer’s composition and concentration which formed nanofibers. Miscibility was integral in the spinnability to produce nanofibers with derived properties. Modification by sequential thermal treatment was applied to enhance the stability and integrity of nanofibers. Characterization of nanofibers showed the effect of blending SDIB with PBz based on microstructure, morphology and final properties. Synergy created by blending revealed an increase in fiber diameter and change in fiber morphology with the occurrence of conglutination with each fibers. SDIB incorporated in the nanofibers were confirmed based on correlation of amount of sulfur content relative to sulfur peaks. Thermal properties indicated that new material was produced with hydrophilic surface and retained solvent resistance. The sulfur groups for ion exchange were relatively low which led to exploration of other functionalization methods. Direct sulfonation of nanofibers resulted to surface chemistry with the presence of sulfonate groups. This modification generated the stimuli-responsive surface wettability of nanofibers. Potential applications of sulfur-bearing nanofibers are metal adsorption and oil-water separation with specific end-use properties determined compared with similar materials.

Abstract Format

html

Language

English

Format

Electronic

Keywords

Sulfur; Copolymers; Nanofibers

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Embargo Period

4-10-2022

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