The transesterification of bisphenol-a polycarbonate (PC) and polybutylene terephthalate (PBTP): A new route to block copolycondensates (original) (raw)
Related papers
Journal of Polymer Science: Polymer Physics Edition, 1982
The structure of the four-component copolyester resulting from the exchange reaction between molten bisphenol-A polycarbonate and poly(buty1ene terephthalate) is analyzed as a function of the reaction time by infrared and nuclear magnetic resonance spectroscopy. By applying a statistical method developed earlier, the mean chain length of the various sequences as well as the degree of randomness is computed. The exchange reaction leads initially to the formation of a block copolyester with reduced solubility. As the reaction proceeds, a solutde random copolycondensate is progressively formed.
New catalysts for poly(ethylene terephthalate)-bisphenol a polycarbonate reactive blending
Journal of Applied Polymer Science, 1995
and 31nstitute of Organo-Element Compounds, Vavilov Str. 28, Moscow 11 781 3, Russia SYNOPSIS The effects of various catalysts on the reactive blending of poly(ethy1ene terephthalate) (PET) and bisphenol A polycarbonate (PC) was investigated. The various catalysts employed for PET syntheses, T~(OBU)~, SmL3, EuL3, Ca + Sb, CeAc,, Er(N03)3-B12C4, and Tb(acac), * diPy (where L is o-formylphenolate; BI2C4 is a crown ether, benzo-12-crown-4; acac is acetylacetonate; and diPy is 2,2'-dipyridyl) have shown a different catalytic activity toward exchange reactions. Solubility tests, in solvents able to separate unreacted PET and PC, and selective degradation of the PC segments, combined with 'H NMR spectroscopy and size exclusion chromatography, made it possible to order the catalysts according to their catalytic activity: Ti(OBu)4 % SmL3 > EuL3 > Ca + Sb > CeAc3 = EP(NO,),-B&~ > Tb(Acac), * diPy = 0.0
Melt transesterification of bisphenol acetophenone–polycarbonate: A kinetic study
Journal of Applied Polymer Science, 2007
This article deals with the development of kinetic parameters for bisphenol acetophenone-polycarbonate made by melt transesterification with diphenyl carbonate. The understanding of the influence of borosilicate glass of the reactor construction materials on the accuracy of the kinetic data is reported. During the development of analytical methods, the use of high performance liquid chromatography-mass spectrometry (HPLC-MS) was proven to be a valid tool to determine the oligomers existing in the reaction mixture. Accurate kinetics parameters were obtained by elimination of the interference of the construction materials. We provide the rate expressions, kinetic parameters [forward reaction frequency factor ¼ 2.456 Â 10 13 6 0.01 (cm 3 / mol) 2 /min, forward reaction activation energy ¼ 45.69 6 0.2 kJ/mol, reverse reaction frequency factor ¼ 2.068 Â 10 14 6 0.01 (cm 3 /mol) 2 /min, and reverse reaction activation energy ¼ 56.37 6 0.1 kJ/mol], and equilibrium constants at various temperatures.
European Polymer Journal, 2008
The transesterification between poly(ethylene terephthalate) (PET) and dibutyl succinate functionalized polyethylene (POF) was studied by preparing blends in a discontinuous mixer in the presence of different Zn and Ti catalysts. In particular the catalytic activities of Zn(OOCCH 3 ) 2 , Ti(OBu) 4 , ZnO and TiO(OCCH 3 ) 2 were compared. The mechanism of reactions occurring in the melt was studied both by a model compounds approach and by characterizing the macromolecular products of the melt processing by means of selective extractions, infrared analysis and the determinations of the molecular weight of PET. The results are discussed in terms of electrophilicity and nucleophilicity of the different catalysts. The catalysts structure also affected the phase distribution. In fact from a morphologic point of view in PET matrix blends the use of zinc derivatives yielded preferentially dispersed-like phase distribution, while the use of titanium derivatives resulted in partially co-continuous phase morphology. The stability of the attained phase distribution was also monitored during compression moulding and it evolved rapidly in fully dispersed phase morphology. The tensile properties of compression moulded films revealed that the occurred reactions and morphological assessment induced a general decrease of tensile modulus and an increase of elongation at break.
2019
In this study, poly carbonate (PC) and poly (ethylene terephthalate) (PET) were reactive melt-blended under two different conditions to produce PC/PET copolymers. For each condition, samples were taken at specified mixing times representative a specific structure of copolymers and each one employed to physically compatibilize a PC/PET blend with a fixed composition. Reactive blending and copolymer structure are described by solubility analysis results. Continues declining and going through a minimum are two trends of solubility versus mixing time depending on reactive blending condition. Decreasing and increasing patterns of solubility curves were attributed to the formation of copolymers with longer and shorter block lengths, respectively, and the level of solubility was related to the amount of produced copolymers. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) techniques were employed to investigate blend compatibility. The content and structure of...
2005
Blends of poly(trimethylene terephthalate)/bisphenol A polycarbonate (PTT/PC) with different compositions were prepared by melt blending. The effect of transesterification on the miscibility and phase behavior of the blends was studied using DSC, DMA, and 1 H NMR. The DMA results revealed a two-phase system with partial miscibility. DSC thermograms of the first heating scan showed a crystallizable system in which addition of PC-phase reduces the degree of crystallinity. However, the cooling and also the second heating scans revealed the complete miscibility of all the blends. It was concluded that annealing at 300°C (to remove thermal history of the blends) caused the constituents to undergo the transesterification reaction, which changes the blend to a miscible system. The miscibility is due to formation of block copolymers with different block lengths which also suppress the crystallization of the system. The degree of randomness and sequence lengths of the copolymers were determined to analyze the extent of transesterification reaction and structure of the system. It was observed that as the reaction progresses, the degree of randomness increases and the sequence length of the copolymers decreases. Moreover, both increase of reaction time and temperature increased the extent of reaction. The results of DSC and 1 H NMR showed that a small amount of reaction is needed to change this system to a miscible blend.
Compatible blends of biorelated polyesters through catalytic transesterification in the melt
Polymer Degradation and Stability, 2011
The transesterification during the melt blending of polylactide (PLA) and poly(butylene adipate-coterephthalate) (PBAT) was investigated in presence of Ti(OBu) 4 as a catalyst. Both the effect of catalyst concentration and reaction duration was considered. The process was studied by analyzing the molecular weight of the polyesters by size exclusion chromatography (SEC). The rheological, thermal and morphological properties of the blends were investigated by melt flow rate, DSC and SEM analyses, respectively. Evidences about the formation of PBAT-PLA copolymers were obtained and discussed. The tensile properties of compression moulded films were also determined and correlated to the structure and phase morphology development of the blends. In particular, the use of Ti(OBu) 4 resulted in the improvement of compatibility. Moreover, the decrease in stiffness and the increase in elongation at break with the increase of mixing time was observed, in good agreement with the improved compatibility of the modified blend.