Composition and Film Properties of Temperature Responsive, Hydrophobically Modified Potato Starch

Abstract

The film-forming properties of hydrophobically modified potato starch were studied to optimize coating and surface sizing formulations for improvement of barrier properties of paper and paperboard. The spontaneous fractionation of a potato starch hydrophobically modified with a quaternary dodecylammonium chloride resulted in an amylose-rich precipitate with properties differing from those of the original starch. Film formation was investigated in the presence of glycerol and poly(vinyl alcohol) plasticizers. Anti-plasticization was found to occur at low and intermediate plasticizer levels but highly flexible, continuous films were obtained when 30 parts of plasticizer were added to 100 parts of dry starch. The highest transparency and greatest flexibility were obtained with glycerol, while the hydrophobic film properties were maintained with poly(vinyl alcohol). A study of the glass transition temperatures and melting behavior of starch-plasticizer films by differential scanning calorimetry gave useful information about the crystallinity of the films.

Hydrophobic copolymers added with starch at the size press of a paper machine: A review of findings and likely mechanisms

“…Retrogradation of starch to be used in surface sizing manifests itself as precipitation from solution and a decrease in the bond-forming ability of the starch. In particular, solutions of freshly cooked mixtures of starch that contain amylose are especially susceptible to retrogradation if they are held for many minutes within a temperature range of about 67 to 89 C (Andersson et al 2008). It is well known that amylopectin, due to its highly branched nature, is resistant to retrogradation (Hsieh et al 2019).…”

“…However, modified starches with a quaternary dodecylammonium chloride is an alternative to traditional plasticizers, especially for use in food packaging films to provide oxygen barrier and oil resistance of food contact paper packaging. The film-forming properties of the hydrophobically modified starch improves barrier properties of paper and paperboard (Andersson et al 2008). A widely used option is to prepare oxidized starch (Lee et al 2002;Mešić et al 2004;Cui and Jing 2012;Iselau et al 2018).…”

“…Due to the abundance of -OH groups, esterification or etherification can be used to increase starch's hydrophobic character. Several such products have shown effectiveness as sizepress additives to increase the water resistance properties of paper (Aloi et al 2001;Mešić et al 2004;Thirathumthavorn and Charoenrein 2006;Andersson et al 2008;Jonhed et al 2008;Zhou et al 2009;Horchani et al 2010;Anttila et al 2012). Of these reports, one of the most striking observations was the much greater hydrophobic effect of long-chain alkyl chains (octenylsuccinate) compared to shorter chains (Anttila et al 2012).…”

“…Glycerol, poly(vinyl alcohol) (PVOH), and rosin all of been shown to be effective as plasticizers (Jonhed et al 2008;Domene-López et al 2018). Andersson et al (2008) showed that a when PVOH and glycerol were separately added to solutions of hydrophobically modified starch, the glycerol rendered the resulting films hydrophilic. By contrast, the PVOH achieved a plasticizing effect without changing the hydrophobic nature of the film.…”

“…Contact angle tests can be used to reveal the extent to which hydrophobic groups are exposed at the surface of a starch-based film (Garrett and Lee 1998;Andersson et al 2008;Anttila et al 2012;Gigac et al 2014;Iselau et al 2015;Wang and Fang 2016;Özdemir et al 2017a,b). By carrying out such tests with both water droplets and diiodomethane, it would be possible to show evidence of the effect of styrene groups in increasing the dispersion component of free energy at the surface (Moutinho et al 2011).…”