Effect of trifluoroacetic acid on the properties of polyvinyl alcohol and polyvinyl alcohol–cellulose composites

• A polyvinyl alcohol reinforcement process with amorphous cellulose is demonstrated.
• PVA–cellulose composites have been synthesized using trifluoroacetic acid (TFA).
• TFA treated PVA films demonstrate exceptional strain at break values around 700%.
• Trifluoromethyl groups induce a certain degree of water resistance.

Highly stretchable polyvinyl alcohol (PVA) films with a strain at break of around 700% were obtained from solutions in trifluoroacetic acid (TFA). Structural and chemical analysis by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (ATR–FTIR) showed that TFA is retained by PVA via hydrogen bonds between the carboxylic acid groups and the hydroxyl groups of the polymers causing a strong plasticizing effect. Additionally, composites of PVA with cellulose could be developed using TFA as common solvent. The morphological and mechanical properties of the polymer composites could be accurately tuned by modifying the relative concentrations of the two polymers. Data from water adsorption isotherms and wetting measurements indicated that the presence of trifluoromethyl groups in PVA render the composite films relatively hydrophobic.

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