Ming Wei Di

Stability and Ageing of Plasma Treated Wood/Polyethylene Composites Surfaces

Wood/Polyethylene (PE) composites were modified by air glow discharge plasma. The modified composites surface were characterized by contact angle measurements, attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that the surface wettability was improved, -OH, C-O and C=O bond were introduced on the surface, the oxygen element content increased and the shear bonding strength increased after plasma treatment. However, in the period of aging, the modified surface was unstable and exhibited a hydrophobic recovery, meanwhile the oxygen-containing functional groups reduced, O/C ratio increased and the shear bonding strength decreased gradually.

Preparation and Mechanical Properties of Lignin/Epoxy Resin Composites

Lignin/epoxy resin composites were prepared by blending lignin with epoxy resin cured by polyamide. The effect of the content of lignin and polyamide on the mechanical properties of the lignin/epoxy resin composites was studied systemically. And the structure for the blend of lignin and epoxy resin without the curing agent was characterized by Fourier transform infrared spectroscopy (FTIR). The results of mechanical properties test showed that the bending strength of the composites decreases gradually with increasing the content of lignin, while the impact strength increased firstly and then decreased. The bending strength of lignin/epoxy resin composites showed a trend of increasing firstly and then decreasing with the increase of the content of polyamide, while the impact strength exhibited an opposite trend. The density for the composites increased with the addition of lignin, and polyamide exhibited an inconspicuous effect on density of the composites. The FTIR analysis results showed that the epoxy resin could be cured by lignin without polyamide, which concluded that the lignin could catalyze the cross-linking of epoxy resin or react with epoxy resin, and this bonding effect would beneficial to the properties of lignin/epoxy resin composites.

Effect of Different Compatibilizing Agents on the Compatibility of Lignin/LDPE Composites

Lignin has been blended with low density polyethylene (LDPE). Maleic anhydride grafted high density polyethylene (HDPE-g-MAH) and Maleic anhydride grafted polypropylene (PP-g-MAH) have been added as compatibilizing agent. The weight ratio of LDPE, ligin and HDPE-a-MAH were 75:25:7.5, 75:25:10 and 75:25:12.5; the weight ratio of LDPE, ligin and PP-a-MAH were 75:25:5, 75:25:7.5 and 75:25:10 respectively. The mechanical properties of the blends were investigated according to Chinese standard GB/1447-2005 and compared with those of lignin/LDPE composites without compatibilizing agent. Scanning electron microscopy (SEM) was used to investigate the dispersion of the lignin and PE and the compatibilizing mechanism was analyzed. The results reveal that addition of compatibilizing agent increased the interfacial bonding strength of the composites, improved the mechanical properties and obtained the better dispersion of the lignin and LDPE with HDPE-g-MAH as compatibilizing agent.

Study on Film of Polyvinyl Acetate Emulsion Modified by Starch

The use of starch on polyvinyl acetate emulsion blend modified in order to achieve improved film toughness, which aims to improve water resistance and film-forming emulsion adhesive performance. Dynamic mechanical properties (DMA), scanning electron microscopy (SEM) method was used to analyze the dynamics of film emulsion blend composite mechanics, the distribution of latex particles and glass transition temperature. The results show that: with pure polyvinyl acetate (PVAc) compared to starch-modified film-forming emulsion film distribution, glass transition temperature of the homopolymer emulsion up to 30°C.

Mechanical Study and Microscopic Characterization of Lignin/PE Composites

The lignin/PE composites with different compatibilizing agents were extruded and the tensile properties have been tested. The weight ratio of PE, ligin and PE-a-MAH were 7.5%, 10%and 12.5wt%; the weight ratio of PE, ligin and PP-a-MAH were 5%, 7.5% and 10wt% respectively. Scanning Electron Microscopic (SEM) was used to characterize the morphology of the composites. The tensile strengths of lignin/PE composites with PE-g-MAH were higher than that one with PP-g-MAH. Both of them were higher than that one without any compatibilizing agent. And PE-g-MAH was the better compatibilizing agent confirmed by the mechanical tests and SEM results.

Preparation of the Plywood Using UF Resin Modified with Blocked Isocyanates

The plywood was prepared using the UF resin modified with isocyanate blocked by sodium bisulfate in this paper. And the effects of the ratio of UF resin and blocked isocyanate, hybrid method and the additive on the properties of the plywood were also studied. The results showed that under the condition of BPI / UF =5%, the order of urea-formaldehyde resin mixed mode curing agent, additive and finally joined the BPI , the bonding strength of the plywood was improved obviously and the formaldehyde release of the plywood could achieve the demand for the national standard.

The Effect of Nano-Filler on the Damping Properties of Polyacrylic Damping Paint

The dynamic mechanical properties of the blends of polyacrylic ester and various nano-fillers and the effect of nano-filler on the damping properties of polyacrylic ester damping paint were studied by using dynamic mechanical analysis (DMA) in this paper. The experiment results showed that the glass-transition temperature (Tg), loss factor peak value and effective damping temperature range for the polyacrylic ester damping paint changed correspondingly after blended with various nano-fillers. The damping properties and effective damping temperature range of the polyacrylic ester damping paint would be improved effectively by adding nano-polyacrylic ester rubber filler; the nano-silicon dioxide could enhance the damping properties for the polyacrylic ester damping paint, but the degree of improvement for effective damping temperature range was inferior to nano-polyacrylic ester rubber filler; and the nano-calcium carbonate could also improve the damping properties of the damping paint, but the effective damping temperature range was hardly improved.

Performances of Polyvinyl Acetate Hybrid Emulsions with Nanoparticles SiO2

Polyvinyl acetate（PVAc）hybrid emulsions with nanoparticles SiO2 were prepared by the semi-continuous seeding emulsion polymerization. The micro-morphologies of the hybrid emulsions, the diameters and distributions of the latex particles were characterized with the aid of scanning electron microscope (SEM) and diameter analyzer. Adhesive properties of hybrid emulsions and the properties of the emulsion films were determined by mechanical properties tester and dynamic mechanics analyzer (DMA). And the rheological behaviors of hybrid emulsions were measured via rheometer. SEM and diameter analysis showed that the process of the nanoparticles SiO2 by ultrasonic made a good dispersibility of latex particles in emulsions, diameters of the latex particles were 0.68~0.89μm with the content of SiO2 from 0 to 1.0% (% in relation to the total mass VAc), and indexes of distributions of particle size were increased with the increasing of the content of SiO2 from 0 to 1.0%. Adhesion strengths of PVAc emulsions modified with nanoparticles SiO2 were improved. DMA results indicated that the films of PVAc/SiO2 hybrid emulsions had the higher storage modulus than the film of PVAc, the temperatures of glass transition of the films of PVAc/SiO2 hybrid emulsions were not changed obviously, and the water absorptions of films were decreased. Rheological results revealed that flow consistency indexes were increased then decreased with the increasing of the content of SiO2 from 0 to 1.0%, and PVAc/SiO2 hybrid emulsions were typical pseudoplastic fluid.

Effect Of PP-G-MAH on the Compatibility of Lignin/LDPE Composites

Lignin have been blended with low density polyethylene (LDPE). Maleic anhydride grafted polypropylene (PP-g-MAH) has been added as compatibilizing agent. The weight ratio of LDPE, ligin and PP-a-MAH were 75:25:5, 75:25:7.5 and 75:25:10, respectively. The mechanical properties of the blends were investigated according to Chinese standard GB/1447-2005 and compared with those of lignin/LDPE composites without compatibilizing agent. Scanning electron microscopy (SEM) was used to investigate the dispersion of the lignin and LDPE and the compatibilizing mechanism was analyzed. The results reveal that addition of compatibilizing agent increased the interfacial bonding strength of the composites, improved the mechanical properties and obtained the better dispersion of the lignin and LDPE.

Compatibility of Lignin/LDPE Composites Modified with HDPE-G-MAH

Lignin have been blended with low density polyethylene (LDPE). Maleic anhydride grafted high density polyethylene (HDPE-g-MAH) has been added as compatibilizing agent. The weight ratio of LDPE, ligin and HDPE-a-MAH were 75:25:7.5, 75:25:10 and 75:25:12.5, respectively. The mechanical properties of the blends were investigated according to Chinese standard GB/1447-2005 and compared with those of lignin/LDPE composites without compatibilizing agent. Scanning electron microscopy (SEM) was used to investigate the dispersion of the lignin and LDPE and the compatibilizing mechanism was analyzed. The results reveal that addition of compatibilizing agent increased the interfacial bonding strength of the composites, improved the mechanical properties and obtained the better dispersion of the lignin and LDPE.