An environmentally friendly clay-based polymer
Wei-Dong Liang, Chen Qian, Zhao-Qi Zhu, Han-Xue Sun, Chong-Hua Ma,
Li-Na Wang, Ran Wang and An Li
An environmentally friendly clay-based polymer composite paper-like film is prepared by
incorporating nanometre-sized attapulgite (ATP) clay crystals into degradable poly(vinyl
alcohol) (PVA) though a simple blending and casting method. X-ray analysis shows that
no changes in the crystalline structure of ATP are observed in the PVA matrix. Even with
50 wt % clay crystals the ATP-PVA composite films show excellent flexibility, and tensile
strength up to 22.19 MPa. The material is printable, tough and flexible. The doping
of ATP also results in flame retardancy, making it an ideal candidate for packing and
building decoration applications.
Sorption and desorption properties of random copolymer
hydrogels of N-isopropylacrylamide and N-ethylacrylamide:
Effect of monomer composition
Chandra Sekhar Biswas, Qiao Wang, Bing Du and Florian J. Stadler
Random copolymer hydrogels of N-isopropylacrylamide and N-ethylacrylamide were prepared
using different monomer compositions in 1:1 methanol–water mixtures. Depending on
the monomer compositions in the synthesis medium, the porosity of the gels varies from a
nonporous to highly porous structure. The surface morphology, swelling properties in water,
cononsolvency properties in different methanol-water mixtures at various temperatures and
deswelling properties are reported. The gels show promise biomedical applications, such as
scaffolds for tissue engineering, scaffolds for three-dimensional cell culture, or thermoresponsive
bioseparation over the wide LCST range observed.
Printed thermoelectric materials and devices:
Fabrication techniques, advantages, and challenges
Michael Orrill and Saniya LeBlanc
Thermoelectric (TE) devices enable increased efficiency and performance by converting waste
heat to usable electricity or providing solid-state, localized cooling. Large-scale implementation
is hindered by power conversion efficiency, manufacturing challenges and material costs.
Traditionally, inorganic compounds are used for their high performance, however they are
brittle, scarce, and toxic. Organic compounds have lower power conversion efficiencies, but
they are flexible, abundant, low-cost, environmentally benign and solution-processable, making
them suitable for large-scale, high-throughput manufacturing techniques. Inorganic–organic
hybrid composite materials can boost power conversions efficiencies while maintaining ease
of processing. Four manufacturing techniques—inkjet, screen, and dispenser printing, and
stereolithography—used to fabricate TE devices are reviewed.
Oxidation resistance and abrasive wear resistance of
vitamin E stabilized radiation crosslinked ultra-high
molecular weight polyethylene
Anuj Bellare, Fabio D’angelo, Hung D Ngo and Thomas S. Thornhill
Gamma radiation is known to increase wear resistance of ultra-high molecular weight
polyethylene (UHMWPE). However, the free radicals generated in the lamellar regions by
the radiation can cause oxidative degradation as the polymer ages. Vitamin E has been
incorporated into highly crosslinked UHMWPEs in an attempt to combat the problem. Here the
wear resistance of irradiated Vitamin E-stabilized UHMWPE under abrasive wear conditions,
and the oxidation resistance of samples that were shelf-aged for two years was assessed.
Swelling experiments show that Vitamin E decreases crosslink density, negatively affecting
wear resistance, but better preserves the oxidation resistance with increasing concentration.