Physical and mechanical testing of essential oil-embedded cellulose ester films

Authors: BASTOS, MARIA - Embrapa; LAURENTINO, LARISSA - Universidade Federal Do Ceara (UFC); CANUTO, KIRLEY - Embrapa; MENDES, LUANA - Universidade Estadual Do Ceara; MARTINS, CAMILA - Embrapa; SILVA, SARAH - Universidade Federal Do Ceara (UFC); FURTADO, ROSELAYNE - Embrapa; Kim, Sanghoon; Biswas, Atanu; Cheng, Huai

Submitted to: Polymer Testing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2015
Publication Date: 12/14/2015
Publication URL: http://handle.nal.usda.gov/10113/62381
Citation: Bastos, M.S.R., Laurentino, L.S., Canuto, K.M., Mendes, L.G., Martins, C.M., Silva, S.M.F., Furtado, R.F., Kim, S., Biswas, A., Cheng, H.N. 2016. Physical and mechanical testing of essential oil-embedded cellulose ester films. Polymer Testing. 49:156-161.

Interpretive Summary: Cellulose is the earth's most abundant biopolymer and is of tremendous economic importance. Celullose products include paper, textiles, construction materials, and cellulose derivatives, such as cellulose acetate. It is estimated that annually 1.5 billion pounds of cellulose acetate are manufactured globally. There is a need to expand the uses of cellulose acetate, especially in food-related areas because of the size of the market and the relevance to consumers. Polymer films made from cellulose esters can be useful in embedding plant essential oils, either for food packaging or air freshener applications. In this work, studies and testing were done on the physical and mechanical properties of cellulose ester-based films incorporating essential oils (EO) from lemongrass (Cybopogon citratus), rosemary pepper (Lippia sidoides), and basil (Ocimum gratissimum) at concentrations of 10 of 20% (v/w). The incorporation of EO reduced tensile strength and Young's modulus but increased elongation at break. Thus, EO acted like a plasticizer and increased the flexibility of the polymer. The thermal and microscopic data were consistent with this understanding. The water barrier property was effectively improved when the film was composed of 20% of the three types of essential oils. However, the essential oils somewhat decrease the transparency of the films. This study indicates that EO-embedded cellulose ester films are particularly suitable for food packaging that requires low water vapor exchanges and decreased sensitivity to light. Farmers may benefit since this work potentially expands the applications of cellulose acetate, which is derived from cellulose from agricultural resources.

Technical Abstract: Polymer films made from cellulose esters are useful for embedding plant essential oils, either for food packaging or air freshener applications. Studies and testing were done on the physical and mechanical properties of cellulose ester-based films incorporating essential oils (EO) from lemongrass (Cybopogon citratus), rosemary pepper (Lippia sidoides), and basil (Ocimum gratissimum) at concentrations of 10 and 20% (v/w). Results obtained showed that, in all films, the addition of the essential oil caused a decrease in the water vapor permeability due to the hydrophobic nature of the oil. The use of 20% of EO caused lower transparency of the films, although the change was not observed visually. Mechanical testing was done on cellulose acetate, cellulose acetate propionate and cellulose acetate butyrate. It was found that incorporation of lemongrass, basil and rosemary pepper EO significantly affected the Young’s modulus, tensile strength and elongation at break of the cellulose ester films. The results suggested that the EO interacted with the polymers like plasticizers. The results were confirmed with thermal and microscopic studies.