Dimethylsiloxane-containing block

Gaines [13] has reported on dimethylsiloxane-containing block copolymers. Interestingly, if the organic block would not in itself spread, the area of the block polymer was simply proportional to the siloxane content, indicating that the organic blocks did not occupy any surface area. If the organic block was separately spreadable, then it contributed, but nonadditively, to the surface area of the block copolymer. 

Films of these materials, which are of the AB type, and contain blocks both of which independently form insoluble monolayers on water, behave quite differently from those with non-spreading blocks. Monolayers of three samples, having dimethylsiloxane contents ranging from 25 to 58% were examined their tt-A curves were nearly identical. The curve for the intermediate material, containing 44.6 wt % dimethylsiloxane (corresponding to a structure (MMA)2oo-(DMS)2i7), is shown in Figure 6. The surface pressure was stable at least to the upper limit of this measurement, and no hysteresis was observed on compression and expansion in this range. 

Trade Names Containing Koster Keunen Emulsifying Wax Enamel whKe. See Barium sulfate English Fuller s earth. See Fuller s earth English whKe. See Calcium carbonate Entol. See Tetrahydroxyethyl ethylenediamine Entsufon Entsufon sodium. See Sodium octoxynol-2 ethane sulfonate Enzactin. SeeTriacetin EO. See Ethylene oxide EO/dimethylsiloxane/EO block copolymer CAS 68937-54-2... 

High soil-release performance, excellent softness and combinability with fluorocarbon finishes may be achieved by special silicone/polyalkylene oxide copolymers. The silicone segments contain hydrophobic dimethylsiloxane structures and hydrophilic silicone modifications with ethoxylated or amino group-containing side groups. The different hydrophilic-lipophilic balance (HLB) of the polyalkylene blocks is adjusted by the ratio of hydrophobic (polypropylene oxide) and hydrophilic (polyethylene oxide) components. 

In this chapter, the properties of a series of poly(dimethylsiloxane-co-methylalkylsiloxane) (PDM-PMAS) of various alkyl side-chain lengths are discussed. These polymers contain 3.5 mol % methylalkylsiloxane units and are prepared from the same precursor thus, any effects due to variations in the percentage of alkyl substitution and main-chain molecular weight differences and effects due to block distribution of the alkyl substituents are eliminated. 

Attempts to synthesize copolymers from D -DiSiAn in which n was >30 failed. Invariably, two immiscible o-dichlorobenzene solutions resulted. Typically, one phase contained low-molecular-weight polymer rich in poly(dimethylsiloxane), and the other contained high-molecular-weight material rich in organic block. Phase separation during polymerization was not encountered when the average siloxane blocks were less than 30 units long. 

Tphe surface activity of block copolymers containing dimethylsiloxane units as one component has received considerable attention. Silicone-poly ether block copolymers (1,2,3) have found commercial application, especially as surfactants in polyurethane foam manufacture. Silicone-polycarbonate (4, 5), -polystyrene (6, 7), -polyamide (8), -polymethyl methacrylate (9), and -polyphenylene ether (10) block copolymers all have surface-modifying effects, especially as additives in other polymeric systems. The behavior of several dimethylsiloxane-bisphenol A carbonate block copolymers spread at the air—water interface was described in a previous report from this laboratory (11). Noll et al. (12) have described the characteristics of spread films of some polyether—siloxane block co-... 

Figure 6. Surface pressure-area curve for MMA-DMS block copolymer (38-1-HI, Ref. 9) containing 44.6% dimethylsiloxane...

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