Philippe Degee

Single-step reactive extrusion of PLLA in a corotating twin-screw extruder promoted by 2-ethylhexanoic acid tin(II) salt and triphenylphosphine

Abstract The ring opening polymerisation of l , l -lactide using an equimolar complex of 2-ethylhexanoic acid tin(II) salt Sn(Oct) 2 and triphenylphosphine P( φ ) 3 as catalyst shows for the first time a reactivity providing a polymerisation propagation rate fast enough to imagine a continuous single-step reactive extrusion process for bulk polymerisation. The ring opening polymerisation has been realised on a corotating closely intermeshing twin-screw extruder, using a specially designed screw concept to provide sufficient energy input and mixing for further enhancement of the propagation rate, without detrimentally enhancing depolymerisation or transesterification reactions. Using one chosen screw and processing concept on a twin-screw extruder with 25xa0mm diameter and a L / D -ratio of 48, the influence of different processing parameters on the resulting molecular parameters of the Polylactide (PLA) has been determined. Furthermore, the mechanical property profile of the generated PLA-polymers is discussed and related to the molecular parameters.

Design of polymer blend rheology: 4. Effect of polymethacrylic ionomers on the melt viscosity of polyamide m x D,6

Abstract Rheological properties of blends of polyamide m × D,6 (PA) with random copolymers of methyl methacrylate and methacrylic acid (P(MMA-co-MAA)) and the related ionomers (P(MMA-co-metal MA)), respectively, have been investigated at 260°C. Addition of small amounts of suitable ionomers (up to 5 wt%) remarkably increases the melt viscosity of PA. At low shear rates and depending on the metal cation of the ionomer, the rheofluidity of PA is reduced by at least two orders of magnitude. The PA melt viscosity increases with the cation as follows: Ni2+

Design of polymer blend rheology

SummaryAddition of small amounts of maleic anhydride containing copolymers remarkably increases the melt viscosity of the m x D,6 polyamides (PA). Random copolymers of styrene and maleic anhydride, P(S-co-MA), have been melt blended with PA in a ratio ranging from 0.5 to 5 wt%. A linear dependence has been observed for the blend viscosity on the molar ratio of the maleic anhydride subunits in the copolymer and the amino end-groups of PA. This linear relationship holds even for blends containing a molar excess of anhydride compared to amine. These rheological effects are of prime importance for the highly desirable control of the PA processing.

Synthesis and characterization of halato-telechelic bisphenol-A polycarbonates

Interfacial polycondensation of bisphenol-A and phosgene is a well-known way to prepare bisphenol-A polycarbonate, the molecular weight of which can be controlled by the addition of suitable amounts of phenol. When the chain stopper is a bifunctional compound, the way is open to the synthesis of telechelic polycarbonates. 4-Hydroxybenzoic acid, 4-hydroxybenzenesulfonic acid, 4 N,N′-dimethylaminophenol and the iodoammonium derivative have been used as bifunctional chain stoppers in the synthesis of acid and amino telechelic polycarbonates. The n.m.r. analysis of the final products has provided evidence for the successful synthesis of α,ω-tertiary amino and α,ω-quaternary ammonium polycarbonates. In contrast, fast transesterification reactions prevent α,ω-carboxylic and sulfonic acid polycarbonate from being prepared in a controlled way.