Study On The Synthesis And Properties Of Polyether Modified Organic Silicon Surfactant

Polyether modified polysiloxnae surfactant is an organosiliconesurfactant with excellent performance, so it is widely used in such areas asfoam stabilizers for polyurethane foams, cosmetic materials, textiles,antifogging agents, addition agents in plasties, sotfening agents and so on.However, the research of organic silicone surfactants has been startedrelatively late, the kind of products is single, and a large production scale hasnot been formed, the most of products are imported. It will decrease theimports of similar products, reduce the dependence of domestic enterprises toforeign enterprise on technology, and improve competitiveness if the organicsilicon additive is developed successfully, which will be beneficial to wideapplication of organic silicone surfactant. Therefore, a series of Polyethermodified silicone surfactants were prepared by hydrosilation. Explore thebest reaction conditions and the influence of the structure of raw material forthe characters of the products, the surface tension of the2%products aqueoussolution and the contact angle in PMMA was determined, the influence onthe performance of the product by the molecular weight of polyether andhydrogen amount of silicone oil was studied. And the performance ofpolyether-modified trisiloxane/tetrasiloxane surfactants was furtherinvestigated and contrasted, The influence on the performance of the productby the product structure on of was comprehensive studied.Firstly, a series of silicone surfactants were prepared by hydrosilationfrom the allyl polyethers with different degree of polymerization and thehydrogen silicone oil with different content of hydrogen, with chloroplatinicacid as catalyst. The reaction conditions such as temperature, time and thedosage of catalyst were investigated. Under the precondition that the reactantratio of allyl polyether to hydrogen silicone oil n(C=C):n(Si-H) was equal to 1.2:1, the optimized reaction condition was obtained by the reference ofproduct appearance, i.e. at100°C with20ppm catalyst (in platinum atoms)for6hours before colorless and transparent products were obtained. Theeffects of content of hydrogen of silicone oil and the molecular weight ofallyl polyether on the appearance of products were also investigated. Itshowed that in the process of hydrosilation those low-hydrogen silicone oilsand allyl polyethers with low molecular weights tend to form homogeneousproducts with transparent appearance.Secondly, a series of polyether-modified silicone surfactants wereprepared under the solvent-free conditions. The surface tension of the2%products aqueous solution and the contact angle in PMMA was determined,The influence on the performance of the product by the molecular weight ofpolyether and hydrogen amount of silicone oil was studied. The resultsshowed that the molecular weight of polyether exists an optimal proportion,which can makes the silicon surfactants has good surface activity and wetability. But when the molecular weight of polyether is more than the bestvalue, the surface activity and wettability of silicon surfactants was abated.Finally, a series of polyether-modified trisiloxane/tetrasiloxanesurfactants (TRSE/TESE) were synthesized by the reaction of allylpoly(ethylene oxide) of different degree of polymerization withl,1,1,3,5,5,5-heptamethyltrisiloxane and1,1,1,3,5,7,7,7-octamethyltetrasil-oxane, respectively. The surface activity and the wettability of the aqueoussolutions of silicone surfactants on PET (polyethylene glycol terephthalate)and PMMA (polymethyl methacrylate) substrates were investigated bysurface tension and contact angle measurement. The solubility of surfactantswas also studied. The effects of structures of hydrophobic group(trisiloxane/tetrasiloxane) and hydrophilic group (the number and the lengthof poly(ethylene oxide) chain) on their surface activity and wettability werediscussed, and the comparison between TRSE and TESE was also made. Itshowed that these two types of surfactants exhibited excellent surface activityand wettability, where the surface activity and wettability of TRSE werebetter than those of TESE. However, their surface activity showed differentrules with the increase of EO chain length: The surface activity of TRSE decreased with the increase of EO chain length while that of TESE showedan optimum at a specific EO chain length (EO number＝8). Both their γcmcvalues only slightly changed in the range of small EO numbers, but theincreasing level of γcmcbecame significant when the EO number was verylarge. In the aspect of wettability, the wettability of TRSE decreased with theEO chain length, while that of TESE changed little at first and then decreasedsignificantly when the EO chain length was very long.