The aims of this study were to form uncompressed thermobonded 3D wool nonwoven shell structures in one continuous process, and to study the controlling factors that govern this process. Lack of bonding between wool fibres and between wool and thermoplastic fibres was attributed to the wool fibre's low surface energy because of the lipids on the outer surface of wool fibres (epicuticle). To overcome this problem, three different surface treatments were investigated; chlorination, Hercosett and plasma. The purpose of these treatments was to raise the surface energy of wool fibres by bond scission and the introduction of new functional polar groups and ablation of the outer lipid layer or membrane. For thermobonding with wool fibres, low melting nylon fibres were chosen because of their high polarity and chemical compatibility with wool fibres. SEM, BSM and ESEM imaging techniques as well as tensile strength testing for single fibres, pair bonded samples and 3D nonwoven shells were used to assess the samples. Results have shown that it is possible to thermobond wool and nylon fibres as 3D shell structures, given that wool fibres are treated appropriately and the bonding temperature is controlled properly. Moreover, it has been found that, for pair bonded samples, the wrapping angle and the bonding angle have significant effects on the tensile strength and number of bonding points. Hercosett treated wool fibres yielded the strongest bonds with nylon fibres followed by plasma, chlorinated and untreated fibres.
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