Fundamentals of Solid State Polymerization

J of Applied Polymer Sci

et al. 2014

The synthesis of aliphatic polyesters (PEs) derived from diols (1,4-butanediol and 1,8-octanediol) and diacids or their derivatives (diethyl succinate, sebacic acid, 1,12-dodecanedioic acid, and 1,14-tetradecanedioic acid) was achieved in order to produce poly(butylene succinate) (PE 4.4), poly(octylene sebacate) (PE 8.10), poly(octylene dodecanate) (PE 8.12), and poly(octylene tetradecanate) (PE 8.14). The herein suggested procedure involved two stages, both sustainable and in accordance with the principles of "green" polymerization. The first comprised an enzymatic prepolymerization under vacuum, in the presence of diphenylether as solvent using Candida antarctica lipase B as biocatalyst, whereas a low-temperature postpolymerization step [solid state polymerization (SSP)] followed in order to upgrade the PEs quality. In the enzymatically synthesized prepolymers, the range of number-average molecular weight attained was from 3700 to 8000 g/mol with yields reaching even 97%. Subsequently, SSP of PE 4.4 and 8.12 took place under vacuum or flowing nitrogen and lasted 10-48 h, at temperatures close to the prepolymer melting point (T m 2 T SSP varied between 4 C and 14 C). The solid state finishing led to increase in the molecular weight depending on the prepolymer type, and it also contributed to improvement of the physical characteristics and the thermal properties of the enzymatically synthesized PEs.

Section: Introductionmentioning

confidence: 99%

Production of biodegradable polyesters via enzymatic polymerization and solid state finishing

Kanelli

Douka

J of Applied Polymer Sci

et al. 2014

“…In order to have an estimation of the molecular size of the formed PA 6.6 nanocomposites, the relative viscosity of all grades, before and after extrusion was measured (Figure 2). 17, 19–24 The obtained η rel values demonstrated an important organoclay influence on the polymerizability of the PA matrix. More specifically, the fully organically exchanged clays, i.e.…”

Section: Resultsmentioning

confidence: 76%

Applying the Traditional Solution Melt Polymerization for the in situ Intercalation of Polyamide 6.6‐Clay Nanocomposites

Boussia

Papaspyrides

2011

Macro Materials & Eng

The traditional PA 6.6 production route, i.e. solution melt polymerization followed by extrusion, is applied to the in situ intercalation of PA 6.6/clay nanocomposites. Organoclays of different types are tested and the derived nanocomposites are thoroughly characterized in terms of molecular weight, thermal properties and morphology. Reaction acceleration is found in the presence of fully exchanged organoclays, which is attributed to a chain extension mechanism based on clay SiOH groups. Analysis of the nanocomposites' nanostructure indicates that the applied solution melt polymerization process results in some flocculation of the tested organoclays, which is improved in some cases after extrusion and leads to partially exfoliated nanocomposites.magnified image

“…Equation (2)(3)(4)(5)(6) were used for calibration of the experimental apparatus and design of the experimental conditions, performed at atmospheric pressure, as illustrated in Figure 3. Apart from proper model calibration, the experimental apparatus was carefully designed in order to allow for adequate control of the RH and temperature.…”

Section: Experimental Part Preliminary Analysis Of Humidity Measurementsmentioning

confidence: 99%

“…[1] Typical industrial processes for production of high-molecular-weight PET involve at least two stages: a melt-state polymerization (MSP) step followed by a solidstate polymerization (SSP). [2] Both stages comprise reversible polycondensation reactions and can be strongly limited by mass transfer effects. As a consequence, removal of volatile by-products is of fundamental importance, as indicated by the temperature-independent low equilibrium constants for transesterification (K eq ¼ 0.5) and esterification (K eq ¼ 1.25 and 2.5 depending on the reacting species bearing the necessary functional groups).…”

Section: Introductionmentioning

confidence: 99%

Solid‐State Polymerization of Poly(ethylene terephthalate): The Effect of Water Vapor in the Carrier Gas

Filgueiras

Papaspyrides

et al. 2010

Macro Materials & Eng

SSP of PET has been thoroughly investigated under the regimes of chemical reaction and particle diffusion control. However, the majority of industrial PET plants operate under conditions of surface by‐product diffusion control, mainly due to recycling cycles of the carrier gas. The presence of residual volatile by‐products in the carrier gas (especially water) may affect adversely the polymerization reaction and the resulting polymer quality. For this reason, the effects caused by varying water vapor content of the carrier gas on the course of the PET SSP are analyzed, with emphasis on the intrinsic viscosity. The presence of small amounts of water in the carrier gas is found to exert a pronounced effect on the course of polymerization, leading to significant reduction of the molar masses of the final product. magnified image