Kinetics of hydrolysis and thermal degradation of polyester melts

Seo, Kab Sik; Cloyd, James D.

doi:10.1002/app.1991.070420330

Cited by 88 publications

(46 citation statements)

References 6 publications

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“…In particular, second-order kinetics lead to single exponential growth for the viscosity. 2 This exponential growth is experimentally observed (see Fig. 2) and predicted by eq.…”

Section: Evolution Of the Linear Viscoelastic Propertiesmentioning

confidence: 59%

Rheological behavior of polyamide 11 with varying initial moisture content

Acierno

Puyvelde

2005

J of Applied Polymer Sci

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ABSTRACT:The rheological behavior of polyamide 11 samples with different initial moisture levels is investigated. More specifically, the time evolution of the linear viscoelastic properties is monitored at a given frequency. The time dependence of these properties is exponential in time, reflecting postcondensation reactions in the samples. The crossover time, at which the storage modulus and loss modulus intersect, can be used as a characteristic timescale for the reaction. This crossover time and the corresponding complex viscosity can be used as fingerprints of the material, reflecting the moisture content in the material.

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“…In particular, second-order kinetics lead to single exponential growth for the viscosity. 2 This exponential growth is experimentally observed (see Fig. 2) and predicted by eq.…”

Section: Evolution Of the Linear Viscoelastic Propertiesmentioning

confidence: 59%

Rheological behavior of polyamide 11 with varying initial moisture content

Acierno

Puyvelde

2005

J of Applied Polymer Sci

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“…Both dry and wet feeding with unmodified fibers resulted in an increased amount of PCL end groups (i.e., PCL−OH) as shown by the doublet at 3.25 ppm, attributed to a beta-scission mechanism caused by the high shear present in the system. 32 In comparison, acetylated fibers show much less degradation due to the absence of PCL end groups suggesting an improved interaction and dispersion of acetylated cellulose fibers in the matrix. 33 From DSC thermograms (Table S2), a very small effect of fiber loading is observed on PCL glass transition temperatures, melt temperatures and melting enthalpies (ΔH m ), suggesting no nucleation effect of cellulose fibers in the already high crystalline polymer matrix.…”

Section: ■ Experiments and Materialsmentioning

confidence: 99%

Poly(ε-caprolactone) Biocomposites Based on Acetylated Cellulose Fibers and Wet Compounding for Improved Mechanical Performance

Spinella

Boujemaoui

et al. 2018

ACS Sustainable Chem. Eng.

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Poly(ε-caprolactone) (PCL) is a ductile thermoplastic, which is biodegradable in the marine environment. Limitations include low strength, petroleum-based origin, and comparably high cost. Cellulose fiber reinforcement is therefore of interest although uniform fiber dispersion is a challenge. In this study, a one-step wet compounding is proposed to validate a sustainable and feasible method to improve the dispersion of the cellulose fibers in hydrophobic polymer matrix as PCL, which showed to be insensitive to the presence of the water during the processing. A comparison between unmodified and acetylated cellulosic wood fibers is made to further assess the net effect of the wet feeding and chemical modification on the biocomposites properties, and the influence of acetylation on fiber structure is reported (ATR-FTIR, XRD). Effects of processing on nanofibrillation, shortening, and dispersion of the cellulose fibers are assessed as well as on PCL molar mass. Mechanical testing, dynamic mechanical thermal analysis, FE-SEM, and X-ray tomography is used to characterize composites. With the addition of 20 wt % cellulosic fibers, the Young's modulus increased from 240 MPa (neat PCL) to 1850 MPa for the biocomposites produced by using the wet feeding strategy, compared to 690 MPa showed for the biocomposites produced using dry feeling. A wet feeding of acetylated cellulosic fibers allowed even a greater increase, with an additional 46% and 248% increase of the ultimate strength and Young's modulus, when compared to wet feeding of the unmodified pulp, respectively.

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“…Recycling of polyester has become an important process from the environmental point of view and it has given commercial opportunity due to wide spread use and availability of PET bottles, packages and fibers [37][38][39]. While mechanical recycling is well established, chemical recycling is highly dependent of the manner in which the depolymerization is carried out.…”

Section: Recycling Of Polyestermentioning

confidence: 99%