Non-isocyanate polyurethane (NIPU) is a novel kind of polyurethane prepared by reaction of cyclo-carbonates and amines without use of toxic isocyanates. NIPU has attracted increasing attention because of its improvements in porosity, water absorption, and thermal and chemical resistance over conventional polyurethanes. Their potential technological applications include chemical-resistant coating, sealants, foam, etc. In this paper, on the basis of a comprehensive survey of the currently available literature on NIPU, we summarize recent progress in NIPU, and mainly discuss the syntheses of cyclo-carbonates oligomers, the reaction mechanism, and the preparation and application of different kinds of NIPU.
Understanding the factors that affect residents’ waste separation behaviors helps in constructing effective environmental campaigns for a community. Using the theory of planned behavior (TPB), this study examines factors associated with waste separation behaviors by analyzing responses to questionnaires distributed in Guangzhou, China. Data drawn from 208 of 1000-field questionnaires were used to assess socio-demographic factors and the TPB constructs (i.e., attitudes, subjective norms, perceived behavioral control, intentions, and situational factors). The questionnaire data revealed that attitudes, subjective norms, perceived behavioral control, intentions, and situational factors significantly predicted household waste behaviors in Guangzhou, China. Through a structural equation modeling analysis, we concluded that campaigns targeting moral obligations may be particularly effective for increasing the participation rate in waste separation behaviors.
A systematic study
has been carried out to develop a material with significant protection
properties
from galactic cosmic radiation and solar energetic particles. The
research focused on the development of hydrogen-rich benzoxazines,
which are particularly effective for shielding against such radiation.
Newly developed benzoxazine resin can be polymerized at 120 °C,
which meets the low-temperature processing requirements for use with
ultrahigh molecular weight polyethylene (UHMWPE) fiber, a hydrogen-rich
composite reinforcement. This highly reactive benzoxazine resin also
exhibits low viscosity and good shelf-life. The structure of the benzoxazine
monomer is confirmed by proton nuclear magnetic resonance and Fourier
transform infrared spectroscopy. Polymerization behavior and thermal
properties are evaluated by differential scanning calorimetry and
thermogravimetric analysis. Dynamic mechanical analysis is used to
study chemorheological properties of the benzoxazine monomer, rheological
properties of the cross-linked polybenzoxazine, and rheological properties
of UHMWPE-reinforced polybenzoxazine composites. The theoretical radiation
shielding capability of the composite is also evaluated using computer-based
simulations.
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