isocyanate (PM-200) with a NCO content of 31.3 wt% and a viscosity of 197 mPa [s.sup.-1] at 25 [degrees]C was provided by Yantai Wanhua Chemical Group Co.
Xu, "Formation of polyphenyl
chains through hierarchical reactions: ullmann coupling followed by cross-dehydrogenative coupling," Chemical Communications, vol.
isocyanate 25.12% 4,4'-Diphenylmethane diisocyanate 20.09% Methylene diisocyanate 12.56% Flash point 199[degrees]C Density 1.13 g/[cm.sup.3] Operational time at room 30 min temperature (21[degrees]C) Clamp time 6 h Table 3.--Southern pine decking board sample characteristics.
Suitable crystallizable polymers include polyethylene glycol (PEG), nylon, polyalkenes, polybutylterephthalates, polyethylene terepthalates, polyvinyl acetates, polyvinyl chlorides, polyphenyl
sulfones, and polycaprolactones.
Examples range from bismuth telluride (1,6) to combinations of bismuth and tellurium and other elements such as antimony and selenium (3,6) to lead-selenium-tellurium (4) to polyphenyl
ether molecule chains (5) to cobaltates on a silicon substrate.
The researchers discovered the potential for converting heat into electricity when they studied polyphenyl
ethers, molecules that spontaneously aggregate into polymers, long chains of repeating units.
The cross-linked siloxane-polyurethane systems that have been reported were prepared by the crosslinking of Si-O-Si through a hydrolysis condensation process (7-8) or by the reaction of NCO and OH groups in the polymethane polyphenyl
polyisocyanate and in the multifunctional polysiloxane polyols, respectively, (9) or by the incorporation of polyhydric alcohols into the polyurethane formulation.
28, the Sentinel published a list of some ingredients of CheckMate, noting that it included polymethylene polyphenyl
isocyanate (PPI), which has been linked to respiratory problems.
Investigation results are presented on degradation transformations in aliphatic-aromatic polyimides and polyamides, polysulfones and polyester imides, liquid-crystal copolyesters, and polyphenyl
quinoxalines in various temperature ranges.
Likewise, SLS can use unfilled and glass-filled nylons, while FDM uses ABS, polycarbonate, and polyphenyl
Stratasys plans to introduce a polyphenyl
sulfone resin for its machines this summer.
SYNTHESIS OF 4,4'-DINITROAND 4,4'-DIAMINO- DERIVATIVES OF CHAIN-TYPE POLYPHENYL