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Copolyamides of PA 66/6 lithium 5-sulfoisophthalic acid (LiSIPA) containing up to 40 mol % of LiSIPA were prepared in a 1L-pilot reactor operating at high pressures and high temperatures. Interestingly, the presence of lithium sulfonate moieties highly impacted the glass transition temperature of the polyamide. The Tg increased from 59 °C for PA 66 to 155 °C for a copolymer containing about 40 mol % of LiSIPA. 1,3-Dihexylbenzenedicarboxamide and lithium p-toluenesulfonate were synthesized as model compounds to investigate the interaction of lithium sulfonate moieties and amide functions. Infrared spectroscopy using ATR technology performed on mixture of both compounds showed that the carbonyl group of amide functions interacts with the lithium cation of lithium sulfonate moieties. Similar SO and CO adsorption bands were observed in copolyamides PA 66/6LiSIPA and in mixture of model compounds, which strongly suggest the formation in the copolyamides of physical cross-linking points centered on lithium cations coordinated by carbonyl groups of amide functions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Polyethylene (PE), alkoxyamine- and thiol-terminated PEs (PE-TEMPO and PE-SH, respectively) can be converted to macroradicals using a peroxide, a thermal cleavage of the alkoxyamine and a hydrogen transfer reaction of the thiol, respectively. The addition of these macroradicals to multiwalled carbon nanotubes (MWCNTs) were compared by performing grafting reactions at 160 degrees C in 1,3-dichlorobenzene as solvent. Raman spectroscopy was utilized to follow the introduction of PE on the MWCNTs' surface while thermogravimetric and elemental analysis indicated the extent of this grafting. The grafting ratio was found to be in the range of 19-36 wt %. PE-functionalized MWCNTs were imaged by transmission elec-tronic microscopy showing a PE layer with various thicknesses covering the surface of nanotubes. It was found that higher levels of grafting were obtained using PE-2,2,6,6-tetramethyl-piperidinyl-1-oxy and PE-SH rather than a radical grafting reaction in which dicumyl peroxide, PE, and MWCNTs were reacted. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 957-965, 2011

Poly(styrene) macromercaptanes (Mn = 1900, 3600, and 6100 g mol-1, PDI ≈ 1.2) derived from thiocarbonyl thio capped polymers prepared via reversible addition fragmentation chain transfer polymerization were employed to initiate the ring opening polymerization (ROP) of D,L-lactide under conditions of organo-catalyis employing 4,4-dimethylaminopyridine. Poly(styrene)-block-poly(lactide) polymers of number average molecular weights up to 25,000 g mol-1 (PDI ≈ 1.2 to 1.6) were obtained and characterized via multiple detection size exclusion chromatography (SEC) using refractive index as well as UV detection. In addition, diffusion ordered nuclear magnetic resonance and liquid chromatography at critical conditions (of both polystyrene as well as poly(lactide) were employed to assess the copolymers' structure. Furthermore, it was demonstrated that polyethylenes capped with a thiol moiety can also be readily chain extended in a ROP employing D,L-lactide, evidenced via NMR and high temperature SEC. This study indicates that the direct use of macromercaptantes is indeed a methodology to switch from a radical to a ROP process. © 2010 Wiley Periodicals, Inc.

A new synthetic strategy, the combination of living polymerization of ylides and ring-opening polymerization (ROP), was successfully used to obtain well-defined polymethylene-b-poly(epsilon-caprolactone) (PM-b-PCL) diblock copolymers. Two hydroxyl-terminated polymethylenes (PM-OH, M-n = 1800 g mol(-1) (PDI = 1.18) and M-n = 6400 g mol(-1) (PDI = 1.14)) were prepared using living polymerization of dimethylsulfoxonium methylides. Then, such polymers were successfully transformed to PM-b-PCL diblock copolymers by using stannous octoate as a catalyst for ROP of c-caprolactone. The GPC traces and H-1 NMR of PM-b-PCL diblock copolymers indicated the successful extension of PCL segment (M-n of PM-b-PCL = 5200-10,300 g mol(-1); PDI = 1.06-1.13). The thermal properties of the double crystalline diblock copolymers were investigated by differential scanning calorimetry (DSC). The results indicated that the incorporation of crystalline segments of PCL chain effectively influence the crystalline process of PM segments. The low-density polyethylene (LDPE)/PCL and LDPE/polycarbonate (PC) blends were prepared using PM-b-PCL as compatibilizer, respectively. The scanning electron microscopy (SEM) observation on the cryofractured surface of such blend polymers indicates that the PM-b-PCL diblock copolymers are effective compatibilizers for LDPE/PCL and LDPE/PC blends. Porous films were fabricated via the breath-figure method using different concentration of PM-b-PCL diblock copolymers in CH2Cl2 under a static humid condition. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 511-517, 2011