Study On Low-temperature Rotator Phase Photopolymerization Of Longchain Acrylate System

Photopolymerization technology is an emerging polymerization technology,which has been widely used in coatings,adhesives,microlithography,dental prosthesis and other fields due to its advantages of low energy consumption and fast polymerization speed.At present,most photopolymerization reactions are carried out at room temperature.At present,most of the photopolymerization reaction is carried out at room temperature,however,due to the fast speed of the photopolymerization process,and the thermal conductivity of the polymerization system is poor,so in the thicker polymerization system,heat is difficult to release rapidly,resulting in the system to produce tens or even hundreds of degrees Celsius of temperature rise.Such large temperature changes can have a detrimental effect on the substrate or surrounding materials of the polymerized system,especially on biological materials that are not resistant to high temperatures.Therefore,low temperature photopolymerization has attracted the attention of researchers.Low temperature conditions can not only adjust the speed of photopolymerization properly,but also help to reduce side reactions in the polymerization.However,when the temperature is greatly reduced,the monomer will change from a low-viscosity state to a high-viscosity state or even a solid state.At this time,the monomer has a weak mobility due to the steric restriction of the surrounding molecules,resulting in the polymerization rate and conversion rate.also decreased.In recent years,it has been reported that radical chain photopolymerization can occur in a special solid phase（rotator phase）with order,so as long as the existence temperature of the rotator phase can be adjusted to a lower temperature range,low-temperature solid-state can be realized.photopolymerization.This study takes long-chain acrylate with rotator phase,constructs a binary blending system,and then further constructs a ternary blending system according to the results of the binary blending system,and studies the phase state change and photopolymerization performance of the blending system by adjusting the difference and proportion of the carbon chain length between different components,and summarizes the phase state change law of the long-chain acrylate blending system to achieve efficient low-temperature rotor phase photopolymerization.Here are the mainly research about my project:1.Firstly,any two of the three compounds hexadecyl acrylate（HDA）,tetradecyl acrylate（TDA）and dodecyl acrylate（DDA）were selected to construct the binary blend system,and the phase states of the binary system were studied.It was found that compared with the reported binary acrylate system,The newly constructed system does have a lower crystal phase to rotator phase transition point(T_C-R)and a wider rotator phase presence interval（（?）T）.When constructing the binary system of TDA and DDA,its T_C-Rcan reach at least-34.65°C.However,due to its unstable phase state,we introduce the binary system into HDA with longer chain and rotator phase itself to achieve the purpose of stable phase state.2.Secondly,we select HDA,TDA and DDA to jointly construct the H/T/D ternary system.The H/T/D system can induce the formation of stable rotator phase.It was found that the HDA with the longest carbon chain in the H/T/D ternary system could stabilize the phase state of the system and broaden（?）T,while the DDA with the shortest carbon chain could reduce the effect of T_C-Rin the whole system.The addition of TDA with medium length carbon chain can enhance the compatibility of the whole system.3.Then,by studying the phase state of H/T/D ternary blend system at low temperature,the ternary blend system with low T_C-Rand suitable（?）T was selected,and the photopolymerization kinetics of the ternary blend system was studied.The photopolymerization conversion rate and polymerization rate of the ternary blend system at different temperatures were tested,and the photopolymerization capacity of the different blend system at low temperature was analyzed.Then,the photolymerization conditions of the system with obvious polymerization ability were optimized,and the conversion rate was increased by about 15%by changing the light intensity and initiator concentration.In addition,we also found that the polymerization reaction existed in the blend system after the light stopped.When the rotator phase photopolymerization light stopped,it was raised to the temperature above the melting point at a certain rate,and finally the conversion rate was nearly 100%.4.Finally,we studied the molecular weight and molecular weight distribution of rotator-phase photopolymerization products of long-chain acrylate blends at low temperature.The experiment proved that rotator-phase polymerization can obtain ultra-high molecular weight polymers that cannot be obtained by liquid phase polymerization,which is also the unique property of rotator-phase photopolymerization of H/T/D system.