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Uron resin, a kind of urea-formaldehyde (UF) resin containing much more uron structure, were prepared. Several modified UF resins were obtained from mixing uron resins with normal UF resins as well as synthesizing UF resin with uron resin as raw material. This work demonstrated that the introducing of the uron structure reduced free formaldehyde content of UF resin and formaldehyde emission levels in bonded plywood panels significantly, the former were reduced by 76% and 84% in the latter. The synthesis time of uron resin can be shortened to 8 hours. The test result of free formaldehyde content, formaldehyde emission levels and bond strength indicated that specimen of 20 parts uron resin synthesized in 8 hours mixed with 100 parts UF resins (F/U molar ratio of 1.3) had a potential advantage to industrial application. The beneficial effect of uron resin on the performance of UF resin can be attributed to the opening of uron cycle structure and the following reaction with free formaldehyde and its oligomeric glycol forms.

The effects of nanosize copper oxide and basic copper carbonate on the physical and mechanical properties of flakeboards were investigated according to ASTM Standard D-1037, and the curing process of phenol formaldehyde (PF) resin containing copper compounds was further investigated using dynamic differential scanning calorimetry (DSC). The results showed that nanosize copper oxide had no or slightly beneficial effects on the mechanical properties and dimensional stability of the flakeboards. While basic copper carbonate increased thickness swelling and water absorption to some extent, the difference was not statistically significant. The DSC results indicated that the comparable activation energy and reaction enthalpy, obtained from nanosize copper oxide treated samples, contributed to the higher degree of conversion of PF resin and undiminished bonding strength of flakeboards, which is probably related to the acceleration of the addition reactions taking place among small molecules in PF resin and the enhancement of heat transfer of composite mat caused by nanosize copper oxide.

Nano CuO and alkane surfactant modified phenol Formaldehyde (PF) resins were applied to manufacture plywood, and physical and mechanical properties, such as shear strength, tensile property, modulus of rupture (MOR), modulus of elasticity (MOE), as well as termite resistance were evaluated. The result showed that the combination of nano CuO and alkane surfactantplayed different effect on tensile strength, and especially on shear strength as evaluated at different test conditions. But it was confirmed to improve the water resistance of treated plywood specimens. The introduction of nano CuO and surfactant did not influence the flexural properties significantly by statistically. The result of termite tests indicated that the weight loss decreases gradually from 31,12% to less than 10,37%, and the mortality increases from 32,61% to higher than 86,35%. And the AWPA rating also rises from 4 (very severe attack) to 7 (moderate attack).

Uron resin, a kind of urea-formaldehyde (UF) resin containing much more uron structure, were prepared. Several modifi ed UF resins were obtained from mixing uron resins with normal UF resins as well as synthesizing UF resin with uron resin as raw material. This work demonstrated that the introducing of the uron structure reduced free formaldehyde content of UF resin and formaldehyde emission levels in bonded plywood panels signifi cantly, the former were reduced by 76% and 84% in the latter. The synthesis time of uron resin can be shortened to 8 hours. The test result of free formaldehyde content, formaldehyde emission levels and bond strength indicated that specimen of 20 parts uron resin synthesized in 8 hours mixed with 100 parts UF resins (F/U molar ratio of 1.3) had a potential advantage to industrial application. The benefi cial effect of uron resin on the performance of UF resin can be attributed to the opening of uron cycle structure and the following reaction with free formaldehyde and its oligomeric glycol forms.

The effects of nanosize copper oxide and basic copper carbonate on the physical and mechanical properties of flakeboards were investigated according to ASTM Standard D-1037, and the curing process of phenol formaldehyde (PF) resin containing copper compounds was further investigated using dynamic differential scanning calorimetry (DSC). The results showed that nanosize copper oxide had no or slightly beneficial effects on the mechanical properties and dimensional stability of the flakeboards. While basic copper carbonate increased thickness swelling and water absorption to some extent, the difference was not statistically significant. The DSC results indicated that the comparable activation energy and reaction enthalpy, obtained from nanosize copper oxide treated samples, contributed to the higher degree of conversion of PF resin and undiminished bonding strength of flakeboards, which is probably related to the acceleration of the addition reactions taking place among small molecules in PF resin and the enhancement of heat transfer of composite mat caused by nanosize copper oxide.

The topological index of a molecular structure correlate certain physicochemical properties such as boiling point and stability of that molecular structure. Recently several topological indices have been introduced and studies have shown their association with certain physical and chemical properties of other molecules. Specifically, Zagreb, Atom-bound connectivity (ABC) and Sanskruti indices have been correlated with extent of branching, enthalpy and entropy of some organic molecules. In this study we have calculated Zagreb, Atom-bound connectivity (ABC) and Sanskruti indices (S) for Copper (I) oxide and Copper (II) oxide CuO. Additionally, from the experimentally available data, we calculated entropy and enthalpy per unit cell for both the oxides and compared with Atom-bound connectivity and Sanskruti indices. It appears that these indices have very poor relation with these physical properties in both oxides of copper and they may need some modifications to show considerable compliance as reported in other organic molecules."