Surface Modification of Cellulose Acetate with Cutinase and ...

Chapter 1
10.1 Surface modification of synthetic fibres
Synthetic fibres represent almost 50% of the worldwide market of textile fibres.
Polyethyleneterephthalate (PET), polyamide (PA) and polyacrylonitrile (PAN) fibres
show excellent features like good strength, high chemical resistance, low abrasion and
shrinkage properties. However synthetic fibres share as common disadvantages high
hydrophobicity and crystallinity which affect, not only wearing comfort, (making these
fibres less suitable to be in contact with human skin), but also processing of fibres,
impeding the application of finishing compounds and colouring agents. Most of
finishing processes/agents are water-dependent which require an increase in
hydrophilicity of fibre surface (Jaffe and East, 1998; Yang, 1998; Frushour and Knorr,
1998; Burkinshaw, 1995).
Currently, chemical treatments with sodium hydroxide are used in industry to increase
hydrophilicity and improve flexibility of fibres. However, chemical treatment extension
is hard to control, which leads to unacceptable losses of weight and strength and to
irreversible yellowing in the case PAN and PA fibres. Besides, this is not an
environmentally appealing process since it requires high amounts of energy and
chemicals that are further discharged to the environment.
A recently identified alternative under study is the use of enzymes for the surface
modification of synthetic fibres (Gübitz and Cavaco-Paulo, 2003). The use of cutinase
on vinyl acetate, (a comonomer in acrylic fibre) was reported for the first time by Silva
and collaborators (Silva et al., 2005). Lipases and esterases are mainly used for
biomodification of PET. Enzymatic hydrolysis of PET fibres with different lipases
revealed to increase hydrophilicity, measured in terms of wettability and absorbent
properties (Hsieh and Cram, 1998; Hsieh et al., 1997). A polyesterase was reported by
Yoon et al (2002), for surface modification of PET and polytrimethyleneterephthalate
(PTT). The authors reported that formation of terephthalic acid, (a hydrolysis product),
could be monitored at 240 nm. The enzymatic treatment resulted in significant
depilling, efficient desizing, increased hydrophilicity and reactivity with cationic dye
and improved oily stain release (Yoon et al., 2002). The production of polyesterdegrading
hydrolases from a strain of Thermomonospora fusca was investigated and
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