Elsevier

Carbohydrate Polymers

Volume 82, Issue 3, 15 October 2010, Pages 1010-1013
Carbohydrate Polymers

Short communication
Influence of surface esterification with alkenyl succinic anhydrides on mechanical properties of corn starch films

https://doi.org/10.1016/j.carbpol.2010.05.041Get rights and content

Abstract

The influence of surface esterification modification, by using dodecenyl succinic anhydride (DDSA) and octenyl succinic anhydride (OSA), on mechanical properties of corn starch films was investigated. The results showed that the surface modifications significantly increased tensile strength and Young's modulus of starch films; the modification decreased elongation at break of starch films at 75% RH but enhanced it at 95% RH. The effects of NaOH aqueous solution treating time on mechanical properties of starch films were more notable at 75% RH than at 95% RH. The films modified with DDSA were more strong and rigid, while the films modified with OSA were more flexible and ductile.

Introduction

There has been a growing interest in development of thermoplastic starch (TPS) because of its biodegradability, availability from renewable resources and low cost (Gandini, 2008, Liu et al., 2009). The hydrophilic nature of TPS leads to its moisture content changing with ambient humidity, which results in its mechanical properties sensitive to humidity. This disadvantage renders TPS unsuitable for many high humidity applications.

Surface modification of TPS products is an effective and promising approach that can lower humidity sensitivity without affecting TPS bulk composition. The superficial hydroxyl groups of TPS products can be substituted by hydrophobic groups or react with cross-linking agents to form starch molecule networks, so that surfaces of TPS products become less sensitive to moisture, moreover, the hydrophobic surface layer formed by surface modification could prevent or delay moisture exchange between environment and TPS products. (Yu and Liu, 2002, Bengtsson et al., 2003, Carvalho et al., 2005, Zhou et al., 2008, Zhou et al., 2009a).

Author's previous works showed that surface esterification modification of corn starch films significantly decreased surface hydrophilic character and moisture absorption of the films especially at higher relative humidity (Zhou et al., 2009b, Zhou et al., 2009c). Since mechanical properties are important criterion for many practical applications of TPS, it is necessary to investigate the influence of surface esterification modifications on mechanical properties of TPS. This article presented the research results.

Section snippets

Materials

The corn starch was supplied by Changchun Jincheng Corn Development Co. Ltd. (Changchun, China). The DDSA (90% purity) and OSA (2-octen-1-ylsuccinic anhydride, 97% mixture of cis and trans) were purchased from Sigma–Aldrich (St. Louis, USA). Glycerol, sodium hydroxide and ethanol were from Beijing Beihua Fine Chemicals Co. Ltd. (Beijing, China). All these chemicals were used as received.

Film preparation and surface modification

TPS films with thickness about 0.18 mm were fabricated by solution casting method (Zhou et al., 2009b). The

Result and discussion

Author's previous work showed the surface esterification modifications, by either soaking starch films in 0.7% NaOH aqueous solution for 60 s and dipping in DDSA diluted five times by ethanol (v/v) (Zhou et al., 2009b) or soaking the films in 1.0% NaOH aqueous solution for 10 s and dipping in OSA diluted three times by ethanol (v/v) (Zhou et al., 2009c) and then heating at 35 °C for 6 h, significantly reduced the equilibrium moisture content (EMC) of the starch films at high relative humidity.

Conclusion

The surface modification through esterification by using DDSA, OSA or a mixture of DDSA/OSA can significantly increase the strength, stiffness and toughness of starch films at higher relative humidity (95% RH); but at 75% RH, only strength and Yong's modulus can be enhanced. The effects of NaOH aqueous solution treating time on mechanical properties of starch films were more notable at 75% RH than at 95% RH. The films modified with DDSA were stronger and more rigid than OSA modified one, while

Acknowledgement

The authors are grateful to the National Natural Science Foundation of China (no. 50673037) for financial support.

References (9)

There are more references available in the full text version of this article.

Cited by (30)

  • Hydrophobically modified polysaccharides and their self-assembled systems: A review on structures and food applications

    2022, Carbohydrate Polymers
    Citation Excerpt :

    By contacting and interacting with Escherichia coli cells, they captured and immobilized the cells via their hydrophobic moieties, and further killed most of the cells because of the disruption effect of cell wall membrane induced by the insertion of hydrophobic chains. Hydrophobization of Ps could improve the characteristics of edible films including water vapor permeability and mechanical properties (Ren et al., 2010; Sun et al., 2020). Li, Ye, et al. (2015) found that the OSA modification could improve the physical, mechanical, and moisture-proof properties of stretchable starch films due to their hydrophobicity and plasticization of octenyl groups in the film formation.

  • Physicochemical properties of dodecenyl succinic anhydride (DDSA) modified quinoa starch

    2019, Food Chemistry
    Citation Excerpt :

    DDSA modified starch enhanced the adhesion strength for applications in plywood industry (Sun, Gu, Tan, Zhang, & Huo, 2018). Surface esterification of maize starch film using DDSA significantly changed the hydrophilic nature and mechanical properties of the film (Ren et al., 2010; Zhou, Ren, Tong, Xie, & Liu, 2009). These previous studies of DDSA modified starch were mostly focused on the preparation and applications.

  • Study on hydrophobic modification of basil seed gum-based (BSG) films by octenyl succinate anhydride (OSA)

    2019, Carbohydrate Polymers
    Citation Excerpt :

    These authors concluded that the reaction of OSA with reactive functional groups along starch molecules was higher than that of DSA (i.e. a higher degree of substitution in the presence of OSA) mainly due to the differences in the alkenyl group chain length. The number of free −OH groups and hence the ability of biopolymer chains to develop hydrogen bonds is reduced at a higher degree of substitution and therefore, an increase in the chain mobility is observed (Ren et al., 2010). Data are the average of at least three independent replicates ± standard deviation.

View all citing articles on Scopus
View full text