Dynamic thermal mechanical analysis method for measuring phase transition temperature of temperature-sensitive hydrogel

Abstract

The invention relates to a dynamic thermal mechanical analysis method for measuring the phase transition temperature of temperature-sensitive hydrogel. The method based on dynamic thermal mechanical analysis (DMA) carries out measurement by employing a penetration-mode probe to simulate a compression mode so as to obtain a curve representing changes of dynamic mechanical parameters with temperature, and thus, a storage modulus (E')-temperature (T) curve and a deformation (dL)-temperature (T) curve can be further obtained; and the phase transition temperature of the hydrogel can be determined according to the initial increasing temperature on the E' curve or the initial attenuation temperature of deformation on the dL curve. According to the invention, the method employs the DMA penetration-mode probe to test a cylindrical or block temperature-sensitive hydrogel sample within a proper temperature range (wherein phase transition temperature is + / - 30 DEG C) so as to obtain the dynamic mechanical temperature curves, so the phase transition temperature value of the hydrogel can be determined. The method provided by the invention overcomes the disadvantages of volatilization of moisture in the process of weighing and cracking and breakage of samples due to long-time soaking in a traditional temperature-variable weighing method, the disadvantage of proneness of a differential scanning calorimetry (DSC) curve to influence of water peaks in a traditional DSC method and the disadvantage of long equilibration time in a traditional ultraviolet (UV) turbidity measurement method. The method provided by the invention has the advantages of small usage amount of a desired sample, simple preparation, easy testing operation and simple and visual data, and is especially applicable to detection of temperature-sensitive hydrogel samples with fast water absorption rates.

Description

technical field [0001] The invention relates to a method for testing the phase transition temperature of thermosensitive hydrogel, in particular to a dynamic thermomechanical analysis method for measuring the phase transition temperature of thermosensitive hydrogel. Background technique [0002] Environment-responsive hydrogel (Hydrogel) is a polymer material with strong hydrophilicity and good biocompatibility. It consists of linear polymer chains cross-linked by chemical reactions or physically entangled to form a three-dimensional network structure. Some segments are solvated by water, and other segments are connected to each other by physical or chemical effects. They swell but do not dissolve in water. Therefore, It has potential application value in the fields of drug controlled release, material separation, tissue engineering and so on. Most of the research on environmental responsive hydrogels focuses on the synthesis and application of temperature-, pH-responsive a...

AI Technical Summary

Problems solved by technology

The variable temperature weighing method has the following disadvantages: on the one hand, the moisture on the surface of the sample is not easy to remove; in addition, during the weighing process of the sample, the moisture in the gel volatilizes, which increases the weighing error; It is easy to break when taking out the weighing, further increasing the weighing error

However, the water content of hydrogel is relatively high. During the temperature rise process, water will evaporate, which will affect the size of the sample modulus. Moreover, water overflows during the phase transition process. The plate chuck has no liquid carrying function, causing water to leak into the instrument. , contaminates the furnace body, therefore, the traditional compression mode is not suitable for directly measuring the phase transition temperature of hydrogels

Images