Oxypropylene group

A more detailed study on foam behaviour and the features of foam column destruction has been performed in [69-71]. Various kinds of surfactants, different foam column heights, foam dispersity and temperatures, were investigated at Ap pgH, including the range of critical pressure drops pcr. The kinetics of establishing a capillary pressure was also accounted for. Used were ionic (NaDoS) and nonionic (Triton-X-100) surfactants as well as some silicon-organic compounds which differed by the number of siloxane, dimethylsiloxane, oxyethylene and oxypropylene groups (KS-1, BS-3 and KEP-2). 

Chem. Descrip. Linear polymer of all oxypropylene groups Uses Component of adhesives used in articles intend for food confacf component of surf, lubricanfs in mfg. of mefallic arfides in confacf wifh food base fluid for formulafed compressor lubricants rubber lubricant coating for hydraulic brake parfs and similar equip. reaefive infermedi-ate in preparation of resins, plasticizers, modifiers, and surfaefants antifoam... 

Ethylene oxide and propylene oxide adducts of polyhydric alcohols and amines are widely used as polyethers in the production of polyurethane foams by reaction with diisocyanate. The physical properties of the foams depend to a certain extent on the chemical structure of these polyethers, so it is very important to establish a method for the identification of the base compounds and for the determination of the proportions of their oxyethylene and oxypropylene groups. 

To determine oxyethylene and oxypropylene groups in the ethylene oxide propylene oxide copolymers, and polyols, the samples were oxypropylated and then oxyethylated, and these were then decomposed as described above for the determination of the polyol base compounds. The FFAP column is operated isothermally at 65 °C and the flow-rate of the carrier gas is regulated at 60 ml/min. 

Tsuji and Kounishi extended this method to the identification of base compounds and the determination of their oxyethylene and oxypropylene group contents (Method 60). 

This acetic anhydride - toluene-p-sulphonic acid cleavage - gas chromatography procedure is capable of determining down to 0.05% of oxyalkylene and oxypropylene groups in polyethers and polyurethanes. 

Reaction of olefin oxides (epoxides) to produce poly(oxyalkylene) ether derivatives is the etherification of polyols of greatest commercial importance. Epoxides used include ethylene oxide, propylene oxide, and epichl orohydrin. The products of oxyalkylation have the same number of hydroxyl groups per mole as the starting polyol. Examples include the poly(oxypropylene) ethers of sorbitol (130) and lactitol (131), usually formed in the presence of an alkaline catalyst such as potassium hydroxide. Reaction of epichl orohydrin and isosorbide leads to the bisglycidyl ether (132). A polysubstituted carboxyethyl ether of mannitol has been obtained by the interaction of mannitol with acrylonitrile followed by hydrolysis of the intermediate cyanoethyl ether (133). 

The secondary hydroxyl groups of these poly(oxypropylene) glycol diols are less reactive than the primary hydroxyl groups of the earlier polyesters. At the time of the introduction of these polyethers, the catalysts then available were insufficiently powerful for one-shot processes to be practical and so these polymers have been used primarily in prepolymer processes. 

Figure 5.10 Dependence of the gel fraction, wg, on molar ratio of [OH]/[NCO] groups, ah, for poly(oxypropylene)triol (Niax LG 56)4,4 -diisocyanatodiphenyl-methane system. The dependence has been reconstructed from data of ref. [78]...

Figure 7. Dependence on the gel fraction, molar ratio of OH to NCO groups, rjj, for poly(oxypropylene) (POP) triol -4,4 -diphenyl-methane diisocyanate (HDI) net-...

Polyethers. Three structurally different polyether diols are mainly used poly(1,2-oxypropylene)diol (PPG), poly(1,2-oxybutylene)diol (B-2000), both terminated essentially by secondary hydroxyl groups, and poly (l,4-oxybutylene)diol, a considerably more reactive component owing to primary hydroxyl termination. Of these the poly(oxypropylenes)... 

Advances in chemical synthesis and in an understanding of the tear film of the eye have resulted in the development of compounds with two or more regions that vary in both their lipophilic nature and binding. The first of these to be tested in the eye was poloxamer 407, a block polymer vehicle with a hydrophobic nucleus of poly-oxypropylene,and hydrophilic end groups of polyoxyethylene. One advantage of poloxamers is their ability to produce an artificial microenvironment in the tear film, which can greatly enhance the bioavailability of lipophilic drugs such as steroids. 

Polyol-Glycerol-based poly(oxypropylene) poly(oxyethylene) polyol capped with (ximary hydroxyl groups, 6000 mol.wt. Isocyanate - modified TDl... 

The oxypropylene chains (polyether groups) of these adhesives include so-called alkoxysilyl groups at the ends of the chains capable of crosslinking with moisture like 1C silicones. The MS adhesives are therefore classified between polyurethanes and silicone adhesives. Because of their hybrid structure, they adhere strongly to many different substrates (PA, PC, PP, EPDM, GFP, practically all metal and glass types), even without primers. These adhesives are resistant to UV radiatiOTi and weather influences. 

In POE nonionics, biodegradation is retarded by an increase in the number of oxyethylene groups. The inclusion of oxypropylene or oxybutylene groups in the molecule tends to retard biodegradation. Secondary ethoxylates degrade more slowly than primary ethoxylates even when both have linear hydrophobic groups. 

Poly(oxazolidone-urethane-isocyanurates) were prepared from an excess of isocyanate-terminated oxazolidone prepolymers and poly(oxypropylene) glycols of different chain lengths via the formation of NCO-terrainated poly(oxazolidone-urethanes) followed by trimerization of the terminal isocyanate groups as shown in the following reaction scheme ... 

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