Polypropylene sulfide

Reddy ST, Rehor A, Schmoekel HG (2006) In vivo targeting of dendritic cells in lymph nodes with polypropylene sulfide) nanoparticles. J Control Release 112 26-34... 

Property Test Method Units PEN Polyimide Polyetherimide Poly(ethylene terephthalate) film Polypropylene sulfide)... 

Figure I. Linear dependence of the apparent bimolecular rate constant of living polypropylene sulfide propagation on the fraction of free ions a with Na + [222] as counterion at -30°C in THF ( ) in THP (V) with fBNa + [222] in...

K (26). The former value leads to an interlonlc distance i equal to 4.6 A according to the classical Fuoss equation. This value Is too small compared to the results obtained for cryptated living polypropylene sulfide (8) and for cryptated tetraphenyl-borides In THF (24). This might mean that either K is not located inside the cavity of the ligand or the oxanion can penetrate into the cavity of the cryptand. This last explanation is consistent with comparative conductivity data made on model compounds (17) as shown in Table III. 

Dielectric constant measurements in carbon tetrachioride and in benzene are used to obtain dipole moments of atactic polypropylene sulfide) chains of sufficiently low molecular weight that excluded volume effects are absent. The results are in very good agreement with RIS calculations. Comparison with previously reported experimental results on the high molecular weight polymer confirm the existence of a significant specific solvent effect on the dipole moments. 

Polypropylene sulfide) is synthesized in both the iosotactlc and atactic stereochemical forms. They are investigated by means of dielectric constant measurements in benzene and CCI4. The experimental results are in good agreement with values predicted from RIS calculations. 

It should also be noted that the viscometric technique can detect the presence of star-shaped aggregates, having the ionic active centers. The addition of ethylene oxide to hydrocarbon solutions of poly(isoprenyl)lithium leads to a nearly two-fold increase in viscosity144). Conversely, this results in an approximately twenty-fold decrease in solution viscosity, after termination by the addition of trimethylchloro-silane. This change in solution viscosity is reflected in the gelation which occurs when difunctional chains are converted to the ionic alkoxy active centers 140,145,146). Branched structures have also been detected 147> by viscometry for the thiolate-lithium active center of polypropylene sulfide) in tetrahydrofuran. 

A polypropylene sulfide polymer with just a single ferrocene unit [88] is formed in the ring-opening polymerisation of propylene sulfide (i.e., methyl thiirane) initiated by fc(SNa)2 (Scheme 5-19). 

Scheme 5-19. Polypropylene sulfide containing a single ferrocene unit.

Self-assembled block copolymers are basically amphilic molecules which contain distinctively different polymers. This block copolymer contains two or more polymers quantitatively in the form of blocks. Some of the block copolymers are polyacrylic acid, polymethylacrylate, polystyrene polyethylene oxide, polybutadiene, polybutylene oxide, poly-2-methyloxazoline, polydimethyl sUoxane, poly-e-caprolactone, polypropylene sulfide, poly-A -isopropylacrylamide, poly-2-vinylpyridine, poly-2-diethylamino ethyl methacrylate, poly-2-(diisopropylamino) ethyl methacrylate, poly-2-(methacryloyloxy) ethyl phosphorylcholine, and polylactic acid. These copolymers contain more than polymers to form certain configurations like linear, branched, patterned. For example, if we take three polymers named A, B, and C, they can be combined to form arrangements AB, BA, AA, BAB, ABCAB, ABCABC, ABABAB, etc. in the form of branched configuration it forms (ABQa, (ABA)a, (AB)4, etc. Depending on the above-mentioned number of blocks, they are named as AB diblock copolymers, ABC triblock copolymers, ABC star block copolymers, etc. The covalent linkage between these different blocks of polymers makes macroscopic phase separation impossible, that is, in its place the phase separation... 

Zh. D. Chernova, K. Kalnins, and G. P. Belonovskaya, IR-Spectroscopic Study of Some Kinetic Characteristics of the Formation of Interpenetrating Polymer Network Systems, Vysokomol. Soedin. Ser. B 19(1) 61 (1977). IPNs of TDI/polypropylene sulfide. 

Frenkel, Sorption of Vapors of a Polar Monomer and Solvents by a Polyisocyanate Network, Vysokomol. Soedin. Ser. B. 19(2), 143 (1977). Sorption of benzene by interpenetrating networks with poly(tolylene diisocyanate). Poly(tolylene diisocyanate)/polypropylene sulfide IPNs. 

A(a)<- by stereoelection the polymerization of the racemic monomer R,S) gives a predominant R oi S polymer polypropylene oxide polypropylene sulfide poly-a-aminoacid A -carboxylic acid anhydride (initiator, aluminum alkyl, Ni carboxylate phosphine). A(b) by stereoelection one enantiomer of racemic mixture polymerises more easily than the other one racemic a-olefin B Chromatography of poly-racemic RRS/SSR oiRR/SS) just some examples are known (not separation but more exactly enrichment)... 

Crystalline polypropylene sulfide has been obtained by polymerization of OA monomers with different catalyst systems, especially powdered KOH, by Spassky and Sigwalt [107] and Furukawa et al [108]. 

Recently, in our laboratory, polypropylene sulfides with an asymmetric lateral aminated chain have been prepared and described by Huguet et al [110—112]. OA oxiranylalkyl-amines have been synthesized by reaction of l-chloro-2,3-epoxypropane on iS-methyl-1-propylamine (XLVa) or S -phenyl-l-ethylamine (XLVh) and the reaction of potassium thiocyanate with the amino-oxiranes gave the thiiranyl derivatives without any perceptible racemization. 

The poly-thio-A -/ -A -(methyl-aminomethyl)-ethylenes are amorphous and stereoirregular, in contrast to polypropylene sulfide obtained with the same initiator, which is highly crystalline but it should be mentioned that one of the asymmetric centers is in the lateral chain and not in the main chain, as it is in propylene sulfide. Optical rotatory dispersion curves are independent of the polymerization conditions, they are complex for poly-thio-A -sec-butyl-A -methylaminomethyl-ethylene in different solvents and simple for poly-thio-A -methyl-A -(phenyl-l-ethyl)-aminomethyl ethylene. The ORD s of the poly-hydrochlorides of both polymers in water are normal but quite different from those of the polyamines. The OA polybases are soluble, when protonated, in strongly acidic media. By addition of dioxane or, better, acetonitile, the polybases remain soluble even for a degree of deprotonation of 45% [112]. By an irreversible methylation by dimethyl-sulfate (>10%), the polybases become water-soluble. The chiroptical properties permit the following conclusions ... 

Until now, it was not possible to find a good fractionating system for polypropylene sulfide obtained by stereoelective processes (see paper of Dr Spassky etal). 

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