Synthesis and characterization of polyethylene glycol-phenol-formaldehyde based polyurethane composite

Abstract

A series of phenol-formaldehyde-polyethylene glycol polyether polyols (PF-PEGs) were synthesized through the condensation polymerization and etherification of phenol, formaldehyde, and poly(ethylene glycol) (PEG) under alkaline conditions and subsequently reacted with 1,6-hexamethylene diisocyanate to obtain polyurethane (PU) films using acetone as solvents. The influence of phenol and formaldehyde to PEG mass ratio ((P + F)/PEG) on the hydroxyl number of PF-PEGs and mechanical properties, thermal stabilities, crystallization behaviors, as well as microstructure of polyurethane composite films were studied using chemical analysis, mechanical tests, thermogravimetric analyses (TGA), dynamic mechanical analyses (DMA), X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), respectively. Results demonstrated that PF-PEGs with (P + F)/PEG of 50/50 had the highest hydroxyl number of 323 mg K(OH)/g. The incorporation of phenol and formaldehyde into PEG improved the mechanical properties of polyurethane films, glass transition temperature (Tg), and thermal properties but resulted in the brittleness characteristic of the composite films and low crystallization properties. Moreover, the synthesis mechanism of PF-PEGs polyurethane composite films was revealed, which would provide a theoretical base for the preparation of the rigid polyurethane foams based on phenolic resins.

Reinforcement of electrospun polyurethane fibers with resorcinol–formaldehyde resin

“…Here, RF resin was used for preparing the PUNRF composites since the hydroxyl groups of RF resin can interact with -NH groups of PUN which would facilitate effective coating of the nanofibers with the resin. 25,26 PU nanofiber mats were impregnated with different concentrations of RF solution (5%-30% wt/vol) to obtain PUNRF composites with varying RF concentrations. Depending upon the concentration of RF solution, the nanofiber exhibited a slight increase in weight gain of about 0.2 ± 0.013, 0.5 ± 0.011, 0.9 ± 0.038, 1.3 ± 0.053 wt% in the case of PUNRF5, PURNF10, PUNRF20, and PUNRF30.…”

Nude and Modified Electrospun Nanofibers, Application to Air Purification

“…Additionally, these polymers also are considered green organic solvents, and are promising solvents for sustainable organic synthesis [ 106 ] and have been used for the development of eco-friendly reactions [ 107 ]. PEG have also been used to prepare novel PEG derivatives as PEGylated−peptide biopolymer conjugates, hydrogels of PEG/DEPEG, PEG-tosylate, -mesylate, -bromide or aldehyde and HS–PEG–alkyne [ 105 , 108 , 109 , 110 , 111 ].…”

Recent Developments in Biobased Foams and Foam Composites for Construction Applications

“…PF foams possess excellent fire retardancy but lack mechanical robustness. Although foam toughness can be enhanced by adding various toughening agents such as polyethylene glycol [153][154][155][156][157][158] prepolymer [159][160][161][162][163][164], and polyvinyl alcohol [165,166], the foam loses its flame retardancy due to the flammability induced by these additives, resulting in a trade-off [130,167]. In an effort to replace highly effective halogen-based flame retardants, some studies have incorporated phosphorus containing compounds in the PF resin [168][169][170][171].…”