Recent Advances in the Preparation and Application of Bio-Based Polyurethanes.

Amid environmental pollution and resource depletion, developing and utilizing biomass resources as alternatives to petroleum is a prominent research focus. Driven by environmental protection and sustainable development, the shift from petroleum-based to bio-based polyurethane is a prevailing trend in polyurethane material development. Biomass sources such as vegetable oil, polysaccharides, and lignin offer extensive application prospects in bio-based polyurethane production.

Preparation of nanocellulose and application of nanocellulose polyurethane composites.

Polyurethane is a widely used material because of its excellent properties. Cellulose is a renewable, biocompatible, and biodegradable natural polymer that also has the advantages of a low density, high porosity, and large specific surface area. There are three main types of common nanocellulose: nanocellulose fibers, cellulose nanocrystals, and bacterial nanocellulose.

High Mechanical Properties of Stretching Oriented Poly(butylene succinate) with Two-Step Chain Extension.

The structure, morphology, fracture toughness and flaw sensitivity length scale of chain-extended poly(butylene succinate) with various pre-stretch ratios were studied. PBS modification adopted from a multifunctional, commercially available chain-extension containing nine epoxy groups (ADR9) as the first step chain extension and hydroxyl addition modified dioxazoline (BOZ) as the second step. Time-temperature superposition (TTS) studies show that the viscosity increased sharply and the degree of molecular branching increased.

Preparation and catalytic properties of poly(methyl methacrylate)-supported Pd obtained from room-temperature, dark reduction of ionic aggregates of the unstable Pd solution ionomer.

A poly(methyl methacrylate)-supported Pd nanocatalyst was successfully prepared from solution reaction of Pd(CHCOO) with a copolymer acid, poly(methyl methacrylate--methacrylic acid) (MMA-MAA). The reaction was carried out in a benzene/methanol mixed solvent in the dark at room temperature (∼25 °C) in the absence of a typical chemical reductant. There was coordination between the Pd nanoclusters and MMA-MAA, resulting in Pd nanoclusters being stably and uniformly dispersed in the MMA-MAA matrix, with an average particle size of ∼2.

Melt Blending Modification of Commercial Polystyrene with Its Half Critical Molecular Weight, High Ion Content Ionomer, Poly(styrene--cinnamic Acid) Zn Salt, toward Heat Resistance Improvement.

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Poly(styrene--cinnamic acid) (SCA), an approach to modified polystyrene with enhanced impact toughness, heat resistance and melt strength.

A poly(styrene--cinnamic acid) (SCA) containing 6.8 mol% of CA, with a (∼217 000) comparable to commercial polystyrene (PS), was successfully synthesised emulsion free-radical copolymerisation as evidenced by 1744 and 1703 cm infrared peak occurrences, respectively characteristic of free and dimeric carboxyl C[double bond, length as m-dash]O stretches. Upon the interchain hydrogen bond cross-linking by CA, the impact toughness of the SCA was considerably improved by 47.

Inside the Ionic Aggregates Constrained by Covalently Attached Polymer Chain Segments: Order or Disorder?

When a small-molecule ionic crystal is group-substituted with polymer chain-segments to form an ionomer, do its constrained ionic aggregates maintain ordered internal structures? This work presents, for a Na-salt sulfonated-polystyrene ionomer, reconciled TEM electron-diffraction schlieren textures and WAXS Bragg-type reflections from the ionic-aggregate nanodomains, which solidly prove the aggregates' internal (mono)crystalline order. The observed DSC endotherm of the ionomer, identified by WAXS as an order-disorder transition interior to its aggregates, gradually becomes enhanced over a 3-month, room-temperature physical aging process, indicating that the aggregates' ordering is a slow relaxation process in which the degree of order increases with time. This work corroborates an uncommon form of order, i.