Teflon, block copolymers

The block copolymer and the microsphere were cast from polymer-benzene solution on a Teflon sheet. The solution was gradually dried at room temperature. Film was microtomed vertically at 80 nm thick by the Ul-traCut-N (Reichert Nissei). In order to obtain enough contrast for TEM observation, the P4VP microdomains in the film were stained with OSO4. The film was observed by TEM (JEOL CX-100) at 100 kV. 

HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HNS NTO NTO/HMX NTO/HMX NTO/HMX PETN PETN PETN PETN PETN PETN PETN PETN PETN PETN RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX TATB/HMX Cariflex (thermoplastic elastomer) Hydroxy-terminated polybutadiene (polyurethane) Hydroxy-terminated polyester Kraton (block copolymer of styrene and ethylene-butylene) Nylon (polyamide) Polyester resin-styrene Polyethylene Polyurethane Poly(vinyl) alcohol Poly(vinyl) butyral resin Teflon (polytetrafluoroethylene) Viton (fluoroelastomer) Teflon (polytetrafluoroethylene) Cariflex (block copolymer of butadiene-styrene) Cariflex (block copolymer of butadiene-styrene) Estane (polyester polyurethane copolymer) Hytemp (thermoplastic elastomer) Butyl rubber with acetyl tributylcitrate Epoxy resin-diethylenetriamine Kraton (block copolymer of styrene and ethylene-butylene) Latex with bis-(2-ethylhexyl adipate) Nylon (polyamide) Polyester and styrene copolymer Poly(ethyl acrylate) with dibutyl phthalate Silicone rubber Viton (fluoroelastomer) Teflon (polytetrafluoroethylene) Epoxy ether Exon (polychlorotrifluoroethylene/vinylidine chloride) Hydroxy-terminated polybutadiene (polyurethane) Kel-F (polychlorotrifluoroethylene) Nylon (polyamide) Nylon and aluminium Nitro-fluoroalkyl epoxides Polyacrylate and paraffin Polyamide resin Polyisobutylene/Teflon (polytetrafluoroethylene) Polyester Polystyrene Teflon (polytetrafluoroethylene) Kraton (block copolymer of styrene and ethylene-butylene)... 

SBS. The diffusion coefficient of cyclohexane at 20°C in an SBS block copolymer was measured as a function of film thickness and casting surface. Films of SBS TR-41-2443 (Shell Chemical Co., Houston, TX) were cast under identical conditions from benzene onto glass. Teflon, or previously cleaned mercury surfaces. The films were allowed to dry for a day by evaporation within a partial benzene atmosphere. The films were dried further in a vacuum dessicator for two days before being used in a sorption experiment. The properties of the copolymer are described in Table I. 

Reagents. Hydroxyethyl methacrylate (HEMA) was extracted with hexane to remove bis-esters and distilled in vacuo, b.p. 69 / 0.1 mm Hg. p-Mltrobenzenesulfonyl isocyanate (b.p. 160 /A mm Hg) was synthesized in 63% yield by phosgenatlon of p-nltrobenzene-sulfonamlde in the presence of butyl isocyanate (9 ). Homo- and copolymers of HEMA were prepared by solution polymerization in DMF in the presence of benzoyl peroxide and the results are summarized in Table I. The hydrolytic stability of the hydrogels was estimated by slurrying 0.5-1.0 g of polymer in 5.0 mL 0.35 KOH in 10 mL culture tubes equipped with teflon lined screw caps. The samples were heated at 100 for up to 24 hr in an aluminum constant temperature block. Immediately upon removal from the heating block, the samples were cooled and acidified with 6N HCl. The precipitated gel was washed and soaked in distilled water for 30 min before the carboxylic acid content was estimated by titration with standard NaOH. 

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