Poly Methylene Diphenyl Diisocyanate Research Articles

Developing 3-layer tea oil camellia (Camellia oleifera Abel.) shells-based particleboard with systematic study on particle geometry and distribution

Tea oil camellia (Camellia oleifera Abel.) shell (TOCS) can annually provide about 1.8-million-ton lignocellulose resources for particleboard manufacturing in China, instead of discharging or burning that cause various forms of environmental pollution. In this study, different TOCS particle sizes were used in the core and surface layers of the 3-layer particleboard to systematically investigate the effects of particle geometry on physical and mechanical properties, besides the macro and micro-structure. The results indicated geometry of TOCS particles in either core or surface layers plays a vital role in the properties of panels. Accordingly, using 100% TOCS particles in the mat-mixture with an overall 5% Polymethylene diphenyl diisocyanate adhesive exhibited a modulus of rupture and modulus of elasticity of 4.07 MPa and 664 MPa, respectively. The lower internal bonding was recorded for the smallest particle size in the core layer. It was also observed that 40% of TOCS particles in surfaces and wood particles in the core resulted in close mechanical properties and surface quality to the control panel. Although, an increase in surface layers particle size caused large inter-particle voids.

Upgrading Sustainable Polyurethane Foam Based on Greener Polyols: Succinic-Based Polyol and Mannich-Based Polyol.

It is well known that the traditional synthetic polymers, such as Polyurethane foams, require raw materials that are not fully sustainable and are based on oil-feedstocks. For this reason, renewable resources such as biomass, polysaccharides and proteins are still recognized as one of the most promising approaches for substituting oil-based raw materials (mainly polyols). However, polyurethanes from renewable sources exhibit poor physical and functional performances. For this reason, the best technological solution is the production of polyurethane materials obtained through a partial replacement of the oil-based polyurethane precursors. This approach enables a good balance between the need to improve the sustainability of the polymer and the need to achieve suitable performances, to fulfill the technological requirements for specific applications. In this paper, a succinic-based polyol sample (obtained from biomass source) was synthesized, characterized and blended with cardanol-based polyol (Mannich-based polyol) to produce sustainable rigid polyurethane foams in which the oil-based polyol is totally replaced. A suitable amount of catalysts and surfactant, water as blowing reagent and poly-methylene diphenyl di-isocyanate as isocyanate source were used for the polyurethane synthesis. The resulting foams were characterized by means of infrared spectroscopy (FTIR) to control the cross-linking reactions, scanning electron microscopy (SEM) to evaluate the morphological structure and thermal gravimetric analysis (TGA) and thermal conductivity to evaluate thermal degradation behavior and thermal insulation properties.

Densification, screw holding strength, and Brinell hardness of European beech and poplar oriented strand boards

ABSTRACTIn this study, selected mechanical properties of beech and poplar oriented strand board such as screw holding strength (SH) and Brinell hardness (BH) as well as the relationship of stress and strain under compression for both species under two temperatures (180°C and 220°C) were examined. Poly methylene diphenyl diisocyanate resinated laboratory-scale boards in different design and density of both species (650 and 720 kg/m3) were prepared. The results showed that density has a positive effect on SH and BH of panels. It was also observed that wood species (beech or poplar) and size of strands (normal or fine size) also effect on SH. Both species showed a specific behavior regarding the lapse of stress and strain during compression.

Enhancing dimensional stability of oriented strand composites within biorefinery

The objective of this study was to investigate the effects of hot water extraction process on the dimensional stability of oriented strand composites. Aspen wood strands were extracted using various severity factor levels. Phenol formaldehyde and polymethylene diphenyl diisocyanate resins were used for production of the oriented strandboard panels. Six panel groups were produced from the extracted or unextracted aspen wood strands. The dimensional stability of the material was evaluated by measures of equilibrium moisture content and thickness swell and water absorption after soaking in water for 2 hours and 24 hours. Results obtained in this study showed that thickness swell and water absorption values significantly decreased with the hot water extraction process, with the thickness swell of phenol formaldehyde bonded panels decreasing 70% after 2 hours soaking. The panels with polymethylene diphenyl diisocyanate resin exhibited lower thickness swell and water absorption relative to the panels prepared with phenol formaldehyde resin. Equilibrium moisture content values of the panels bonded with both phenol formaldehyde and polymethylene diphenyl diisocyanate resin decreased with the extraction process. The findings of this work indicate that hot water extraction process could be effectively used to produce oriented strand composites having an enhanced dimensional stability property.

Dynamic mechanical thermal analysis (DMTA) of cellulose nanofibril/nanoclay/pMDI nanocomposites

Cellulose nanofibrils and montmorillonite nanoclay were used to reinforce polymethylene diphenyl diisocyanate (pMDI) resin at loading levels ranging from 1 to 5%. Laminate sandwich samples were prepared using nano-reinforced resin and wood strands. The laminate samples were analyzed for viscoelastic properties using dynamic mechanical thermal analysis (DMTA). Results obtained in this study showed that storage modulus, final cure temperature, and storage modulus at final cure of the pMDI resin were affected by nanoparticle reinforcement. The highest storage modulus was obtained for the 1% cellulose nanofibril reinforced pMDI-wood laminate sample. It was found that the neat pMDI resin had a slightly higher (max %3.82) final cure temperature compared with the pMDI resin reinforced with cellulose nanofibril or nanoclay at different loading levels.

Characterization of Rigid Polyurethane Foam Prepared from Recycling of PET Waste

Poly (ethylene terephthalate) (PET) waste bottles were recycled to prepare RPUFs (rigid polyurethane foams) by using propylene glycol (PG) in different glycol/polymer molar ratios. The glycolysis products were characterized, after that, they reacted with poly methylene diphenyl diisocyanate (PMDI) in the presence of blowing, co-blowing and second blowing agents to produce the RPUFs. The prepared foams were characterized and compared to foam that is produced by original polyol. It was found that the glycolysis products have possibility for the fabrication of RPUFs with proper properties depending on the blowing agent type and density, also they have similar thermal stability compared to that one produced by original polyol. This may provide an advantage in the future planning for recycling of PET bottles to enhance the mechanical and thermal properties of PU.

Properties of particleboard produced using a sealed press

In this study, different properties of experimental particleboard produced using a sealed press were determined and were compared with those for particleboard produced using a conventional press. Three types of binder, namely urea formaldehyde (UF), melamine formaldehyde (MUF), and polymethylene diphenyl diisocyanate (PMDI), were used for board production. For the UF-bonded boards produced using the sealed press, the modulus of rupture and the internal bond strength (IB) decreased due to the high temperature and steam pressure used in comparison to the conditions in a conventional press. However, MUF- and PMDI-bonded boards had improved IB and thickness swelling (TS). For the PMDI-bonded boards, especially, the TS was further improved and IB was increased by using a sealed press. PMDI is known to possess superior properties and was confirmed to achieve good properties when used as a binder for particleboards produced using a sealed press.

Calorimetric and rheological study of isocyanate–pyrolysis oil blends

AbstractThe reaction of polymethylene diphenyl diisocyanate (pMDI) with pyrolysis oils (PO) was studied by differential scanning calorimetry (DSC) and rheology. Chemical reactions between pMDI and PO occur under 100°C, as shown in DSC scans. DSC analysis showed that the peak temperature of the reaction decreased as the PO content of the PO–pMDI blends increased. The heat of reaction is at its maximum around 30–40% PO content. A rheological study of various PO–pMDI blends was done to evaluate the evolution of viscosity with time for different PO–pMDI hybrid mixtures. The initial viscosity of the blends is directly proportional to the PO content. An exponential increase of viscosity was demonstrated for all PO–pMDI mixtures. Rheological and chemical analysis results confirmed that chemical reactions occur between pMDI and PO at room temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1362–1370, 2003