CONDUCTIVE COMPOSITES FROM POLYPYRROLE ELECTROPOLYMERIZED IN A POLYURETHANE MATRIX

In order to improve the mechanical properties of polypyrrole, composites were made by electropolymerizing polypyrrole in a polyurethane matrix. Polypyrrole/polyurethane (PPY/PU) composite films containing CLO_4^-, BF_4^- or CH_3-C_6H_4-SO_3^- counter ions were made in a variety of solvent systems and characterized by SEM, electronic conductivity, FTIR, and mechanical properties. Composite films showing much greater fiexibility than pure polypyrrole were obtained, but their electronic conductivities were substantially lower. Measured eonductivities ranged from 0.001 to 8 S/cm, tensile strengths from 44 to 592 psi, and elongation to failure from 3 to 70%.

A Novel Ternary Composite of Polyurethane/Polyaniline/Nanosilica with Antistatic Property and Excellent Mechanical Strength:Preparation and Mechanism

Antistatic and strength properties are of vital importance for polyurethane rubber used in moving parts of many industrial instruments.Herein,polyurethane was composited with polyaniline and nanosilica based on in situ synthesis of polymer and physical mixing of these fillers to reach desired antistatic and mechanical properties.Chemical,morphological and thermal properties of the polyurethane/polyaniline/nanosilica composites were studied.The electrical resistivity of the composite decreased from 1.1×10^(6)MΩto 7.6×10^(4)MΩas a result of the addition of 4%polyaniline.The tensile strength and elongation at break of the polyurethane composites improved by nearly 300%and100%,respectively,when compared with those of the neat polyurethane.The electronic resistance of PU/PANI/NS ternary is low enough for its antistatic property and decreases with the increase of the added nanosilica,which is unexpectedly and rather significant.Our results would shed light on the development of antistatic PU with excellent mechanical performance.

Durable flame-retardant,smoke-suppressant,and thermal-insulating biomass polyurethane foam enabled by a green bio-based system

Bio-based polyurethane foam has attracted increasing attentions due to eco-friendliness and fossil feedstock issues.However,the inherent flammability limits its application in different fields.Herein,we demonstrate a green bio-based flame-retardant system to fabricate polyurethane foam composite with durable flame retardancy,smoke suppression,and thermal insulation property.In this system,the green bio-based polyol(VED)with good reactivity and compatibility plays a role of flame retardant and EG acts as a synergistic filler.As a result,the LOI value of foam composite increased to 30.5 vol.%and it achieved a V-0 rating in the UL-94 vertical burning test.Additionally,the peak heat release rate(pHRR)and the total smoke production(TSP)decreased by 66.1%and 63.4%,respectively.Furthermore,the foam composite maintained durable flame retardancy after accelerated thermal aging test,whose thermal-insulating property was maintained even after being treated in high-humidity environment with 85%R.H.for a week.This work provides a facile strategy for durable flame retardancy and long-term thermal insulation performance,and creates opportunities for the practical applications of bio-based foam composites.