Preparation and Properties of Salt Ions Modified Thermoplastic ι-Carrageenan Films
Water and salt ion(Ca2+,Na+and Mg2+)solutions were respectively used as plasticizer and crosslinking agent to prepare thermoplasticι-carrageenan films.The effects of type and concentration of salt ions on the structure and properties of carrageen films were studied.The experimental results show that carrageenan can be thermoplastic processed in hot press under the action of water,and the optimal mass ratio of carrageenan/water is about 1:0.8.The structure and properties of carrageen film are influenced by the plasticizing effect of processing and electrostatic synergy of salt ions.As the ionic radius decreases(Ca2+＞Na+＞Mg2+),the hydration of salt ion is enhanced(Ca2+＜Na+＜Mg2+),the plasticizing effect,film light transmittance and thermal stability of thermoplastic carrageenan decrease successively.Compared with unmodified carrageenan film,the fracture strength and elongation at break of carrageenan modified with salt ions are improved,which indicates that the electrostatic action of salt ions can increase the entanglement between the molecular chains of carrageenan and improve its mechanical properties.Compared with the three salt ions,the tensile strength and elongation at break of Ca2+modified carrageenan increase from 4.94 MPa and 6.4％to 10.18 MPa and 9.2％,respectively.Due to the lower hydration of Ca2+and higher electrostatic action of the bivalent ions,the mechanical properties of carrageenan materials are better than those of the other two salt ions.
ι-carrageenansalt ion solutionthermoplasticitymechanical property
NETL
NSTL
万方数据
