No abstract

Boron modified phenolic (BPF) resins with different boron amounts were synthesized with a special synthesis technology. The structure of BPF resin was analyzed by Fourier transform infrared spectra (FTIR) and its curing behavior was analyzed by differential scanning calorimeter (DSC). The results showed that boric acid reacted with the hydroxyl groups in phenolic resin to form a new cross-linked bond such as B-O. At the same time, the heat resistance of BPF resin was improved about 18% with addition of boric acid of 0.8wt%. The obtained BPF had a high curing temperature of 254.6when the boric acid amount was 0.8wt%.

The liquefaction of corncob in polyhydric alcohols was investigated by using sulfuric acid as a catalyst. Results showed that the best liquefaction could be obtained with residue percent of 4.5% under the conditions with the corncob/polyhydric alcohols mass ratio of 1/5, reaction temperature of 150°C, reaction time of 60 min, catalyst amount of 3% (based on the weight of corncob), PEG 400/glycerin mass ratio of 7/3 in the polyhydric alcohols, respectively. The liquefied liquid products had acid number of 18.9 mg KOH/g and hydroxyl number of 616.3mg KOH/g, respectively.

The liquefaction of cellulose in the presence of phenol without or with sulfuric acid as catalyst was investigated. The liquefied products were characterized by GC/MS and FTIR. Results showed that reaction temperature and reaction time had obvious effects on liquefaction of cellulose. Sulfuric acid showed an excellent catalytic degradation. The chemical compositions of the liquefied products produced using sulfuric acid catalyst or not were almost identical, and the majority of the identified liquefied products were methylene bisphenol and its isomers. During the process of liquefaction, the degradation of cellulose and condensation polymerization occurred at the same time. The last liquefied products were greatly dependent on the reaction conditions.

The liquefaction of cellulose in the presence of phenol without or with sulfuric acid as catalyst was investigated. The liquefied products were characterized by GC/MS and FTIR. Results showed that reaction temperature and reaction time had obvious effects on liquefaction of cellulose. Sulfuric acid showed an excellent catalytic degradation. The chemical compositions of the liquefied products produced using sulfuric acid catalyst or not were almost identical, and the majority of the identified liquefied products were methylene bisphenol and its isomers. During the process of liquefaction, the degradation of cellulose and condensation polymerization occurred at the same time. The last liquefied products were greatly dependent on the reaction conditions.

This paper aims at making a study on the bonding properties of birch with API adhesive. A non-formaldehyde adhesive to improve the bonding strength and water resistance of the emulsion was investigated. The adhesive was a composite system that was formulated from polyvinyl acetate (PVAc) emulsion, PVA, isocyanate and some other additives. In this study the effect of isocyanate at room temperature on the curing behavior of PVAc was investigated. A XPS technique has been established to analyze structure of crosslinking in bonding interface. The experimental results indicated that the occurrence for chemical reaction between PVAc-based API adhesive and birch wood.

Curing is the key to the bonding, the study indicate that: curing effect on the glue bond strength, formaldehyde emission as well as Productive Efficiency; the better curing system can ensure the Productive Efficiency in basic to decrease the FE. This paper considered the production practice, studied the curing properties of different MUF resin with TGA. The experimental result: Different curing systems, made different curing process. For A curing system, curing rate is the fastest, the degree of curing is best. Cured stability is well. While in the C curing system, Because of their poor degree of cross-linking, poly-condensation cross-linked imperfect. While, Along with the increasing of n(F):n(U1), initial decomposition temperature increased, the maximum rate of mass loss moved to higher temperature, mass loss declined, decomposition activation energy increases, aging resistance increased.

Curing is the key to the bonding, this paper considered the production practice, studied the curing properties of different MUF resin under the different curing agent with DSC. The experimental results show that: The characteristics temperature of curing reaction is closely related to the β. With the increase of β, the initial and peak temperature is moving to the high-temperature, the curing time became shorter; the range of curing temperature became much wider. At the same time, the curing peaking temperature was decreased and the Enthalpy integral of curing reaction was reduced first then increased with the increased of the amount of curing agent. When the amount of curing agent occupied 4.0%-6.0% of the MUF resin, the pH was decreased mostly, and the curing reaction rate run up quickly Along with the increasing of n (F): n (U1), the To, Tp and Ti are going ahead distinctly after hardening. At the same time, both activation energy and reaction order are all decreased, absorbed heat is dropping too. So, curing technics became easily.