Preparation of epoxy hardeners from waste rigid polyurethane foam and their application

Abstract

SYNOPSISAliphatic amines were used as decomposer to decompose waste rigid polyurethane and polyisocyanurate foams, and the obtained decomposed products were directly used as curing agent of epoxy resin. Effects of the decomposing condition including amine type, foamdecomposer ratio, and reaction temperature on the decomposition reaction and properties of the decomposed products were investigated. Using amines with low molecular weight could enhance decomposition reaction rate and total amine number and lessen viscosity of the obtained decomposed products. Viscosity of the decomposed products decreased with increase of reaction temperature, but increased with increment of foam-decomposer ratio. Shear strength of adhesives consisting of decomposed products and epoxy resin was measured, and their thermal properties were analyzed. The adhesives could be cured completely over 6OoC and their shear strength enhances with adding coupling agent in the adhesive system. The adhesives have good thermal stability and show satisfactory shear strength with more than 15, 15, 7, and 3 MPa at 25, 60, 100, and 150°C, respectively. The results demonstrate that the obtained adhesive systems can be used as structural adhesive. 0 1995

Chemical degradation of thermoplastic polyurethane for recycling polyether polyol

“…Current methods for chemical degrading polyurethane into low molecular weight compounds include glycolysis [3][4][5][6][7][8][9][10][11][12], hydrolysis [13][14][15], aminolysis [16,17] and other chemical processes [18][19][20][21][22]. Among these chemical-recycling processes, glycolysis is much favored and has been paid more attention due to its mild reaction conditions and highly reproducible properties of the recycled products.…”

The Structure and Properties of the Degradation Products of Diethylenetriamine Polyurethane Based on 1,5-naphthylene Diisocyanate

“…On the basis of literature data [8][9][10][11][12][13][14] and the results of GLC-MS and IR spectroscopy, it can be assumed that the degradation of PU (I) by diethylenetriamine proceeds at the start by the mechanism of aminolysis, with the formation of glycols and urea derivatives based on 1,5-naphthylene diisocyanate and DETA. Then the reaction proceeds by the mechanism of hydrolysis.…”

“…On the basis of literature data [8][9][10][11][12][13][14][15][16][17] and the results of IR spectroscopy and gas-liquid chromatography coupled with mass spectrometry, the scheme of the degradation of PU (I) by DETA can be assumed to be as shown in Figure 8.…”

Synthesis of poly(p‐diphenylmethylterephthalamide) from recycled monomers

“…The obtained products from these reactions are predominantly the monomers of PET such as TPA, ethylene glycol (EG), or bis(hydroxyethyl) terephthalate (BHET) 6–10. On the other hand, aminolysis of certain polyurethanes (PU) can yield MDA 11, 12. Therefore, in this research, PMAs were prepared from both pure and recycled TPAs and MDAs, and their thermal properties were studied.…”