Biomaterial Database

Structure and properties of urea-plasticized starch films with different urea contents. 2014

Jia-Li Wang, and Fei Cheng, and Pu-Xin Zhu

Textile Institute, Sichuan University, Chengdu 610065, PR China; Sichuan Research Institute of Silk Industry, Chengdu 610031, PR China.

Films of thermoplastic starch (TPS) plasticized with different contents of urea were prepared by using a solution casting method. Scanning electron microscopy, X-ray diffraction and IR spectroscopy were used to characterize structures of the TPS films, respectively. Water vapor sorption isotherms and tensile properties of the films were determined. TPS films showed more smooth and transparent in appearance and less B-type crystallinity than the starch film without urea. The effect of urea content on the structure and behavior of the TPS film could be divided in three stages: (1) below urea 10% where urea interacted with starch via H-bonding and the films showed an antiplasticization effect, (2) from urea 10% to 30% where an apparent plasticization effect appeared on the starch because of free urea molecules as the effective plasticizer, and (3) a macroscopic phase separation occurred due to supersaturation of urea when urea content was more than 30%.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D010968	Plasticizers	Materials incorporated mechanically in plastics (usually PVC) to increase flexibility, workability or distensibility; due to the non-chemical inclusion, plasticizers leach out from the plastic and are found in body fluids and the general environment.	Plasticizer
D013213	Starch	Any of a group of polysaccharides of the general formula (C6-H10-O5)n, composed of a long-chain polymer of glucose in the form of amylose and amylopectin. It is the chief storage form of energy reserve (carbohydrates) in plants.	Amylomaize Starch,Amylum,Cornstarch,Keoflo,Starch, Amylomaize
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol
D014835	Volatilization	A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.	Vaporization,Volatility
D014867	Water	A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Hydrogen Oxide
D055595	Mechanical Phenomena	The properties and processes of materials that affect their behavior under force.	Mechanical Concepts,Mechanical Processes,Mechanical Phenomenon,Mechanical Process,Concept, Mechanical,Concepts, Mechanical,Mechanical Concept,Phenomena, Mechanical,Phenomenon, Mechanical,Process, Mechanical,Processes, Mechanical