Polypropylene glycols synthesis

Figure 10.1 Temperature dependence of the H T2 relaxation time of well-defined end-linked (PPO) networks with narrow molecular mass distributions between chemical crosslinks [44], The molecular mass of network chains (in g/mol) is shown in this figure. The temperature dependence of a linear, high-molecular-mass polypropylene oxide) prepared from a polypropylene glycol precursor (with a molecular mass of 4000 g/mol) using a chain extender with a chemical structure similar to that of the crosslinker is shown for comparison. The synthesis of the model networks has been...

Polyether polyols, especially polypropylene glycols, have lower functionality than is theoretically due to the presence of side reactions during synthesis (see details in... 

The presence of the polyether monol leads to very modest properties of polyurethanes based on polypropylene glycols obtained by anionic catalysis. In polyaddition reactions involved in polyurethane synthesis a monofunctional polyether is a chain stopper and... 

For the synthesis of urethane-acrylate prepolymer, hexamethylene diisocyanate (HDI, 0.178 moles,) was placed in a reaction vessel, then 2-hydroxyethyl-acrylate (HEA, 0.178 moles) was added. The reaction temperature was kept at 45°C for 30 min., to avoid thermal polymerization through the vinyl groups, then a stoichiometric quantity of dry polypropylene glycol (PPG) (MW 725, hydroxyl number 147 mg of KOH/g (67.4 ml.)) was added along with dibutyl-tin-dilaurate as a catalyst... 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes NFPA Health 0, Flammability 1, Reactivity 0 Storage Store in cool, dry area hygroscopic Uses Intermediate in synthesis of org. compds., polyester and alkyd resins, polypropylene glycol solvent, emulsifier in paints, foods, pharmaceuticals substitute for... 

Like the dicarboxylic acid portion, a mixture of glycols may be used in resin synthesis. Commonly used are ethylene glycol, bisphenol A, trimethylolpropane, and the various polyethylene and polypropylene glycols. The selection depends on the properties needed in the intermediate resin and in the cured product. 

Ethylene and propylene, the simplest alkenes, are the two most important organic chemicals produced industrially. Approximately 26 million tons of ethylene and 17 million tons of propylene are produced each year in the United States for use in the synthesis of polyethylene, polypropylene, ethylene glycol, acetic acid, acetaldehyde, and a host of other substances (Figure 6.11. 

The triblock terpolymer polypropylene oxide)-h-poly[2-(dimethylami-no)ethyl methacrylate]-b-poly[oligo(ethylene glycol) methacrylate], PPO-fc-PDMAEMA-fc-POEGMA, was prepared using the PPO macroinitiator followed by the addition of CuCl, HMTETA, and DMAEMA for the polymerization of the second block and finally OEGMA for the synthesis of the final product (Scheme 54) [128]. 

Oh SJ, Jung JC, Zin WC (2001) Synthesis and surface property variations of polypropylene-graft-poly(eth-ylene glycol). J Colloid Interface Sci 238 43 7... 

Among the most commonly used thermosensitive polymers are poly(iV-isopropylacrylamide) (pNIPAAm) and pluronics (polyethylene glycol-b-polypropylene oxide-b-polyethylene glycol, PEG-h-PPO-h-PEG). The most extensively studied thermosensitive polymer is pNIPAAm with an LCST of 32°C. This has been used as a hydrophobic block of polymeric micelles with a PEG corona, as well as a hydrophilic shell combined with several other hydrophobic blocks. Work on the synthesis and applications of NIPAAm polymers as components for DDS (in most cases micelles) has been extensively described in several reviews over the years (Aoshima and Kanaoka, 2008 Schmaljohann, 2006 TaleUi and Hennink, 2011 Wei c/ /.,2009). 

ManufJDi rib. Advanced Synthesis Tech. Aldrich BASF GFS ISP Speclrom Chems. Lab. Prods. Universal Preserv-A-Chem Trade Nesnes Containing Armohib 28 Propasol solvent P. See Propylene glycol n-propyl ether Propathene. See Polypropylene... 

The free polyalkalene glycol found in these copolymers is normally PEG, since ethylene oxide is generally added last during synthesis. Its formation is initiated by water impurities during the addition of EO to the polypropylene oxide base. The molecular weight of PEG is usually significantly less than that of the main product. 

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