Yan Hua Zhang

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.

Preparation of Plywood Using Starch Adhesives Modified with Isocyanate

The purpose of the study was to manufacture plywood using starch adhesives modified by isocyanate, the influence factors on the bonding strength and water resistance of starch adhesive were studied by different solid content, adding additives and adding isocyanate. X-ray photoelectron spectroscopy (XPS) analysis was used to characterize the chemical structure of bonding interface. The results show that the bonding strength of starch adhesive was increased significantly when solid content increased to 50%. Bonding strength and water resistance were improved significantly by adding additives and isocyanates to starch adhesive. The analysis of XPS indicated that the chemical bonding derived from the reactions of isocyanate was the key factor to increase bonding strength and water resistance.

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.

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.

Mechanical Properties of Wheat Straw Particleboard Using Composite Adhesives

The purpose of the study was to use a cheap wheat straw to manufacture particleboard. Wheat straws offer great promise and new challenges as replacement for wood in processed wood products. The particleboard was produced using composite adhesive which the urea-formaldehyde (UF) adhesives modified by emulsifiable polymeric methylene diphenyl diisocyanate (EPU). The properties of the particleboard was evaluated by measuring internal bonding strength(IB), thickness swelling, modulus of rupture(MOR), modulus of elasticity (MOE) and formaldehyde emission. The optimal condition was chosen at density of 0.75g/cm3, UF/EPU ratio of 70/30, adhesive amounts of 10% based on the dry amounts of wheat straw. The test results showed that maximum dry internal bonding strength, wetting internal bonding strength, modulus of rupture, modulus of elasticity was 0.45MPa, 0.072MPa, 31.50MPa and 4564MPa, respectively. The thickness swelling (TS2h) and thickness swelling (TS24h) was 3.51% and 11.1%, respectively. The free formaldehyde of wheat straw particleboard reached E0-type national standards.

Preparation of Particleboard Made from Wheat Straw with Low-Formaldehyde-Emission Composite Adhesive

This research attempted to prepare the E0 type wheat straw particleboards with low emission formaldehyde composite adhesive. The composite adhesive combined UF resin and blocked polyisocyanate with low deblocked temperature was synthesized with sodium bisulphate as blocking agent. The effects of different blocking agents, mol ratio, reaction temperature and time on block reaction were studied. The influence of mixed ratio of composite adhesive on the performance of wheat straw particleboard was investigated.

The Improvement of Mechanical Properties of Polyurethane Coating by Multi-Walled Carbon Nanotubes

Mechanical properties of polyurethane coating were improved by multi-walled carbon nanotubes (MWNTs) via in situ polymerization and blending polymerization. Fourier transform infrared spectroscopy (FT-IR) measurement was employed to assess the influence of acid treatment on MWNTs. Mechanical properties analysis of polyurethane coatings including tensile strength, elastic modulus, hardness, flexibility, impact resistance were employed to assess the improvement of mechanical properties of polyurethane coating by MWNTs. The results indicated that MWNTs could improve the mechanical properties of polyurethane coatings, and the improvement of polyurethane coatings by MWNTs via in situ polymerization were better than via blending polymerization, and the improvement of polyurethane coatings by acid-treated MWNTs were better than by raw MWNTs.