Renewable polyamides via thiol-ene ‘click’ chemistry and long-chain aliphatic segments

• Published in: Polymer (Guilford) Vol. 153; pp. 183 - 192
• Main Authors: Nguyen, Phan Huy, Spoljaric, Steven, Seppälä, Jukka
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 26.09.2018; Elsevier BV
• Subjects: Acids; Aliphatic compounds; Atomic radius; Condensation; Elasticity; Hydrogen bonding; Hydrogen bonds; Impact resistance; Molecular weight; Monomers; Organic chemistry; Permeability; Polyamide; Polyamide resins; Polyamides; Polymers; Sulfur; Tear strength; Temperature; Thiol-ene ‘click’ chemistry; Water absorption; Water vapor; Polyamide; Impact resistance; Thiol-ene ‘click’ chemistry
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2018.08.033

Thiol-ene ‘click’ chemistry was utilised to prepare dicarboxylic acid monomers containing two sulphur units within the backbone, which subsequently underwent polycondensation to yield a series of renewable, long-chain, fatty-acid derived linear polyamides. The linear sulphur-containing polyamides displayed number-average molecular weights of 8000–55,000 g·mol−1 and broad polydispersities biased towards higher weight fractions. Glass transition values were slightly above room temperature (31–35 °C), while melting temperatures ranged from 121 to 170 °C. This novel class of polymers exhibited an impressive property profile, most notably exceptional impact resistance, tear strength, high elasticity, very low water absorption yet high oxygen- and water vapour permeability. The presence of sulphur and the increased aliphatic segment length influenced a wide spectrum of polyamide properties due to the reduced amide linkage (and inter-chain hydrogen bonding) density and less-effective chain packing ability due to the increased atomic radii of the sulphur atoms. The data highlights the technical advantages of these polymers, while also expanding the repertoire and structure-property relationships of both long-chain- and sulphur-containing polyamides, and encouraging further development of polyamide derivatives from renewable sources. [Display omitted] •Renewable sulphur-containing polyamides were synthesised via ‘click’ chemistry.•Polyamides displayed exceptional impact- and tear resistance, low water absorption.•Polyamides also displayed high oxygen- and water permeability.•Properties influenced by the presence of sulphur and long repeating-unit length.