It is found that the optimum formulation(mass) is polyether polyols(average functionality ≈ 4) 100 parts,mixed delay catalyst YC-1 0.8 parts,water 0.6￣1.0 parts,physical foaming agent 5￣8 parts,foam stabilizer B8870 1.0￣ 2.0 parts; the isocyanate index is 1.05￣1.15;
In comparison with unmodified epoxy resin,the impart strength of modified epoxy resin by FH type polyether polyols has increased by124%,the fracture toughness ratio by89%,and the fracture energy ratio by260%.
The experimental results showed that the relation between temperature and viscosity of polyether polyols agreed with the Arrhenius formula, and the flow activation energy of the polyether polyols was 51.4kJ/mol;
The optimum reaction conditions are reaction temperature of (80±5)℃,prepolymerization time of 1.5￣2h,water mass fraction of <0.05% in polyether polyol,molar ratio of NCO to OH of 1.00￣1.03,post curing time ≥4h.
The properties of a flexible polyurethane foam made from the graft polyether polyol and conventional soft polyether 3010 (mass ratio 50/50) and other material are below: density 27 kg/m 3, tensile strength 128 kPa, tear strength 175 N/m, compression load (at 65% ILD) 598 N/(0.0323 m 2), elongation 107%, rebound 27%.
The result shows that,the foam plastic prepared with coordinate mix of polyol including polyether polyol OH value(410±30) mgKOH/g and OH value (450±30) mgKOH/g,and polyester polyol OH value(400±30) mgKOH/g has better density and compressive strength and meets the requirement of multifunction sandwich production.
The results show that a polyether polyol with good physical properties is obtained when starting temperature is about 130℃, mass fraction of catalyst DMC is 30 × 10-6 and starting pressure of PO is low.
Weight loss of the PU was monitored gravimetrically along with time changing, tensile properties monitored as a function of degradation time that indicated the modified PU could be degraded, when the weight ratio of polyether-polyol and lactic acid was 1.25, and the temperature is 80 the sample became fragments and lost the properties of utilization after 50 hours of degradation in water.
Hydrogen bonds between surface silanol groups and oxygen atoms of the polyether ring of the crown ether play an important role in the immobilization of the reagent.
Electrochemical properties of membranes based on macrocyclic compounds containing two sulfur atoms in a polyether ring were studied.
The electrochemical properties of membranes based on dibenzo-crown ethers bearing hydroxyl and chloromethyl groups in polyether rings were studied.
Selective Oxidation of Ethylbenzene by Molecular Oxygen: Effect of Macrocyclic 18-Crown-6 Polyether Additives on Catalysis by Bi
The catalytic activity of the two-component catalytic system based on nickel bis(enaminoacetonate) (enamac) and 18-crown-6 (18C6) macrocyclic polyether is studied in ethylbenzene oxidation by molecular oxygen.
The results show that the viscosity of polyether polyol increases exponentially from 62 mPa·s to 6 000 mPa·s with the increase of functionality from 2 to 5.6, respectively.
This decrease in bond strength is due to a change in the OH number of the polyether polyol used.
Highly oil-absorbent polyurethane foam (PUF) materials were obtained by polymerizing polyether polyol mixture and carbodiimide-modified d-methyl diisocyanate in a weight ratio of 10:2.
Two tetrafunctional poly-isocyanate energetic curing agents with different molecular weight (EO03-1 and EO03-3) were synthesized via reaction of azido polyether polyol with hexamethylene diisocyanate (HDI).
PCS is based on the synthesis of a hydrophilic polyether polyol and a polyisocyanate to the isocyanate-pre-polymer.