Papers by Keyword: Prepolymer

Abstract: The carboxyl terminated poly (L-lactic acid) (PLLA) prepolymers were prepared via polycondensation of L-lactic acid and 1,6-adipic acid (end capping agent) under the catalyst of stannous octoate. The effects of synthetic condition, such as reaction temperature, amount of catalyst, content of the end capping agent, etc, on the molecular weight of PLLA were discussed. Fourier transform infrared and ¹H nuclear magnetic resonance were used to characterize the PLLA prepolymers. The results indicated that the polycondensation was performed under an optimum reaction condition as following: the amount of the catalyst was 500 ppm based on the mass of lactic acid, the amount of the end capping agent was 1% (the molar amount of the lactic acid), and the polymerization temperature was 170 °C. The viscosity-average molecular weight of the product reached 2.826×10⁴ at this polymerization temperature and the yield was 73.34%.

Abstract: UV-Curable Coatings, Have been Widely Used in Machinery, Chemical Engineering, Biology, Medicine, Electronics and so on, due to their Fast Curing, Low Curing Temperature, Low VOC Emissions and Low Energy Cost. however, the Volume Shrinkage during the Curing Process Have a Great Influence on the Performance of the Coating, which Ofen Lowering Coating Adhesive Strength and Accelerating the Aging Process of Coatings Film.The Paper Select Different Kinds of Monomers (EOEOEA, HDDA, TPGDA, NPGDA, TMPTA and EO₃- TMPTA) and Light Cured Resin (free Radical Type: Polyester Acrylate Resin 5600, Polyurethane Acrylate UA VP 2396, the Pure Acrylic 6536-1,cationic Resin: Epoxy Cationic Resin Omnilance OC3005) to Prepare the UV Curing Coatings. Study on the Influence of Amount of Monomer and Polymer on Polyreaction Reaction by Using Orthogonal Experimental Design Method in Order to Choose the Monomer and Polymer that has the Least Volume Shrinkage Rate, then Develop Photocureable Coating Based on Free Radical Type and Cationic Resin above. the Results Indicate that the UV-Light Photocureable Coating Prepared by Single Functionality Monomer EOEOEA and the DPGDA that Doesn’t Have Neat Molecular Structure has the Less Volume Shrinkage Rate; however, in the Aspect of Prepolymer, the Preparation of UV-Light Photocureable Coating Based on Polyester Acrylate 5600 has the Least Volume Shrinkage Rate. Rely on the Experiment Results above, Prepare the New Kind of UV-Light Photocureable Coating that has Little Volume Shrinkage Rate.

Abstract: UV-curable adhesive has the characteristics of energy conservation , environmental protection and fast curing. As countries around the world pay more and more attention to the environment problem , the development of UV curable adhesive is also growing rapidly. This paper introduces the composition of UV curable adhesive (prepolymer ,active diluent, photoinitiator, additives), and introduces the UV-curable adhesive several huge potential application fields in detail.

Abstract: Plastic UV frosted ink is a novel frosted ink used for the plastic substrate,As a kind of environmental printing ink, plastic UV frosted ink is attracting more attention in the application of the food packaging printing Adherence is an important performance of Plastic UV frosted ink which has directly effect on the quality of the coating and the following process. Different prepolymers, monomers and additives plastic UV frosted ink samples prepared to test their adhesion on PET substrate,explores the prepolymer, kind and content of monomer and additives for plastic UV frosted ink adhesionThe results showed that type and content of the prepolymer, monomer and additives had significant effect on the adhesion force of ink. Adhesion force of sample prepared by polyurethane prepolymer was the best. The higher degree of functionality, volume shrinkage was greater, the adhesion force was worse. An appropriate amount of additives could improve the adhesion force of ink.

Abstract: The reaction mole ratio of monomers, pH value, reaction temperature and time factors directly affect the properties of urea-formaldehyde resin (UF)/low melting point paraffin wax microcapsules during in situ polymerization process. The effects of these factors on the thermal storage capacity, particle size and distribution were systematically discussed. When the reaction conditions were formaldehyde and urea molar ratio of 1.8:1, the prepolymerization system pH controlled at 8.5, the reaction temperature of 60 °C, the reaction time of 60 min, the synthetic phase change materials microcapsules have good morphology and thermal storage capacity.

Abstract: A new prepolymer of polyurethane acrylate (PUA) was synthesized from cyclohexanone- formaldehyde resin (CFR) with high hydroxyl value, toluene diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) by using dibutyltion dilaurate as catalyst via two steps. The result from Fourier transform infrared spectrum (FT-IR) showed that methacrylate group was introduced into the terminal of CFR by using TDI as bridge and curable PUA was obtained. Then, the PUA was cured by using azodiisobutyronitrile as catalyst at 110-130°C for 2h. The resulting product has excellent solvent resistance.

Abstract: There is more and more wide application of UV offset ink in green printing and packaging areas. The offset ink is emulsified inevitably and it will cause a great influence on the ink properties. UV offset ink samples prepared with different prepolymers. Base on the measurements of flow curve, thixotropy and dynamic viscoelastic properties under different emulsification ratio to explore the influence of emulsification on the rheological properties of UV offset ink as well as the effect on the rheological properties with different prepolymers at maximum emulsification ratio. The results indicated that the ink viscosity, thixotropy and dynamic viscoelastic properties decline as the increase of emulsification ratio. Compared with polyester prepolymer ink sample that the emulsified ink sample with epoxy prepolymer shows a faster declined in viscosity, lower thixotropy and larger G’ value. This variation trends relate to the viscosity and net structure of the emulsified ink system.

Abstract: With the aim to study the effect of prepolymer on performance of UV ink-jet yellow ink , prepare UV ink-jet yellow ink color paste by change prepolymer and pigment/binder , test it’s particle size and distribution, explore the effect of different prepolymers and pigment/binder on the dispersion property; make ink color good dispersion paste into ink by using different film forming prepolymers, test the surface tension , viscosity , and curing speed, explore the effect of different prepolymers on the performance of UV ink-jet ink. The results indicate that, prepolymer on the dispersion property has great influence, color paste prepared by prepolymer CN2303 at pigment/binder for 2:1 has minimum particle size, and has good dispersion, film forming prepolymers has great influence on viscosity and curing speed of ink, has little effect on the surface tension of ink.

Abstract: Through the graft copolymerization of LLDPE and the AA-MMA prepolymer by reactive extrusion on the single-screw extruder, the LLPE-g-AA-MMA was prepared and used as compatibilizer for starch/PE blends, and then the compatibilization effect was investigated. The results exhibited that the addition of this compatibilizer substantially improved the mechanical properties, especially the tensile strength. Scanning electron micrographs of the blend specimens also supported the above observations.

Abstract: A kind of form stable phase change material (PCM) based on expanded perlite, paraffin, urea formaldehyde hybrids is prepared by using vacuum-impregnation process. This kind of form stable PCM is made of paraffin as a dispersed phase change material and expanded perlite as a supporting material, and urea-formaldehyde resins as membrane materials to be applied to the porous surface of expanded perlite(EP). The structure of urea-formaldehyde resins(UF) being prepared is characterized by Fourier Transform Infrared Spectrophotometer(FT-IR). Hybrids’ thermal stability, latentheat and morphology are characterized by the thermogravimetry analysis(TGA), differential scanning calorimeter(DSC) Method and scanning electronic microscope(SEM), respectively. The FT-IR and SEM curves show that urea-formaldehyde resins have already been formed. The TGA analysis indicates that the form-stable phase change material has very good thermostability under working atmosphere. The application of DSC not only studies the appropriate curing time of UF，but also indicates that the form-stable PCM that has been prepared has more stable thermal energy storage performance than the traditional one.