丙烯酸烯丙酯的合成

本文介绍丙烯酸烯丙酯的合成原理、路线及最佳工艺条件的选择。

Vapor-Liquid Equilibrium Data of Carbon Dioxide＋Methyl Propionate and Carbon Dioxide＋Propyl Propionate Systems

High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate＋carbon dioxide and propyl propionate＋carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry＇s coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

An Approach to the Flame Retardancy of EVA Copolymer by Plasma Treatmentc2

An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications

Synthesis and characterization of hybrid organic-inorganic materials based on EA-MAn-APTES and silica

Poly (EA-MAn-APTES)/silica hybrid materials were successfully prepared fromEthyl acrylate (EA), maleic anhydride (MAn) and tetraethoxysilane (TEOS) in the presence of acoupling agent 3-aminopropyltriethoxysilane (APTES),by free-radical solution polymerization and insitu sol-gel process. The mass fraction of TEOS varied from 0 to 25%. The hybrid materials werecharacterized by the methods of FT-IR spectra, solvent extraction, scanning electron microscope (SEM), transmission electron microscope (TEM), differential scanning calorimetry (DSC) andthermogravimetric analysis (TGA) measuring apparatus to get their structures, gel contents,morphologies, particle sizes and thermal performances. The results show that the covalent bonds arebetween organic and inorganic phases, gel contents in the hybrid materials are much higher, theSiO_2 phase is well dispersed in the polymer matrix, silicon dioxide exist at nanoscale in thecomposites and have excellent thermal stability.

Preparation and Characterization of Two-component Waterborne Polyurethane Comprised of Water-soluble Acrylic Resin and HDI Biuret

A two-component waterborne polyurethane(2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU parti-cles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI iso-cyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction be-tween HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.

Modified graphite filled natural rubber composites with good thermal conductivity

The rubber composites with good thermal conductivity contribute to heat dissipation of tires. Graphite filled natural rubber composites were developed in this study to provide good thermal conductivity. Graphite was coated with polyacrylate polymerized by monomers including methyl methacrylate, n-butyl acrylate and acrylic acid. The ratios between a filler and acrylate polymerization emulsion and those between monomers were varied. Eight types of surface modification formulas were experimentally investigated. Modification formula can affect coating results and composite properties greatly. The best coating type was achieved by a ratio of1:1 between methyl methacrylate and n-butyl acrylate. The coating of graphite was thermally stable in a running tire. Filled with modified graphite, the tire thermal conductivity reached up to 0.517–0.569 W·m-1·K-1. In addition, the mechanical performance was improved with increased crosslink density, extended scorch time and short vulcanization time.

Evaluation of Impact Strength and Micro-Hardness of Denture Base Acrylic Resin （PMMA） Part Ⅱ

Poly （methyl methacrylate） is widely used as denture base material. During fabrication of a denture, the physical and mechanical properties are influenced by cure condition. Each cure cycle or fabrication technique is attempts to optimize the properties for a given application. The aim of this study was to compare two types of commercially available denture base materials （heat-cure and self-cure） in their mechanical properties. The samples were prepared according to the daily routine work for sample preparation in dental laboratories. After reaching dough stage the mix packed into dumbbell shaped of stainless steel mould and pressed in a hydraulic bench press for 25 mins at room temperature. For heat cure the polymerization cycle was carried out using water bath, while self cure was done at room temperature. The impact strength was evaluated using Charpy impact test. The hardness test was conducted using a calibrated Vickers hardness tester machine. The lowest impact strength was observed in self-cure denture base material （self cure material 6.2 kJ/m^2 while heat cure 12.69 kJ/m^2. It appears that the tendency of heat cure to fracture was lower than self-cure denture base materials. Heat cure denture base material has significantly higher hardness test values than self-cure denture base material. The observed VHN value of the heat-cure was 20.09 g/mm^2 while the self-cure value was 12.7 g/mm^2. This is may be due to the plasticizer effect of residual monomer which was higher in self curing material as reported in previous work. Generally, the heat cure material showed better properties compared to self cure material.

HIGH SOLIDS-CONTENT NANOSIZE POLYMER LATEXES MADE BY A MODIFIED EMULSION COPOLYMERIZATION

Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.

Environmentally Degradation of r-PMMA/PMMA-Blend-PU/Ecoflex Sheet

Poly （methyl methacrylate） scrap was applied to prepare the impact modification of r-PMMA/PMMA-blend-PU/Ecoflex sheet by casting process. The Ecoflex and polyurethane were used as biodegradable polymer and impact modified respectively. This research was ascertained tile way to reduce the processing cost of PMMA sheet and the industrial waste by recycled PMMA scrap into the production process. The r-PMMA/PMMA-blend-PU/Ecoflex sheet was studied potential degradation by landfills for six months. After degradation the percentage of weight loss of specimens was increasing depend on amount of Ecoflex content and degradation period. While, the surface morphology of r-PMMA/PMMA-blend-PU/Ecoflex sheet after six months was damaged and demonstrated that Ecoflex had an effect on PMMA-blend-PU sheet in potential biodegradation. The mechanical and physical properties of r-PMMA/PMMA-blend-PU/Ecoflex sheet were described. Finally, the impact strength of r-PMMA/PMMA-blend-PU/Ecoflex sheet from this research, it is possible to use r-PMMA and Ecoflex in the acrylic casting sheet product.

A novel method for fabricating polydimethylsiloxane microfluidic chip master molds

We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly(methyl methacrylate) (PMMA) was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips.

Bio-inspired shape-memory structural color hydrogel film

Structural colors,derived from existing natural creatures,have aroused widespread attention in the materials regulation for different applications.Here,inspired by the color adjusting mechanism of hummingbird,we present a novel shape-memory structural color hydrogel film by introducing shape memory polymers(SMPs)into synthetic inverse opal scaffold structure.The excellent flexibility as well as the inverse opal structure of the hydrogel films imparts them with stable stretchability and brilliant structural colors.Benefiting from the transient structural anisotropy of copolymers,the hybrid films are possessed with shape-morphing behaviors capability.Based on the shape transformations and color responsiveness performance,we have demonstrated diverse structural color actuators with complex shapes for different tasks.Notably,as the photothermal responsive graphene quantum dots were integrated into the hydrogel,the hybrid films could also be endowed with the feature of light-controlled reversible deformation with synchronous structural color variation.These features demonstrate that the presented shape-memory structural color hydrogel film is valuable for soft robotics with multifunctions of sensing,communication and disguise.

Metal-film-assisted ultra-clean transfer of single-walled carbon nanotubes

Transfer printing of nanomaterials onto target substrates has been widely used in the fabrication of nanodevices, but it remains a challenge to fully avoid contamination introduced in the transfer process. Here we report a metal-film- assisted method to realize an ultra-clean transfer of single-walled carbon nanotubes （SWCNTs） mediated by poly（methyl methacrylate） （PMMA）. The amount of PMMA residue can be greatly reduced due to its strong physical adhesion to the metal film, leading to ultra-clean surfaces of both the SWCNTs and the substrates. This metal-film-assisted transfer method is efficient, nondestructive, and scalable. It is also suitable for the transfer of graphene and other nanostructures. Furthermore, the relatively low temperature employed allows this technique to be compatible with nanomaterial-based flexible electronics.