Analysis of branched poly(ethylene terephthalate)

Abstract

SynopsisPoly(ethylene terephthalate) modified with l,l,l-trishydroxymethyl propane (THP) and pentaerythritol was analyzed with respect to branching by combined GPC/viscometry measurements. The average effective functionality of the branching molecules was calculated and compared with the theoretically attainable functionality, thus permitting one to distinguish between different branching theories. Maximum effectiveness was achieved only at low concentrations of the modifiers added. Pentaerythritol and THP were found equivalent in the ratio 1 : 3, estimated from their influence on the polydispersities of the branched polyester. It was shown that apparent molecular weights obtained from GPC calibration with linear standards can be converted by correction factors. The resulting molecular weight averages of the branched PET samples were in a good agreement with those from the GPC/viscometry iteration procedure.

Influence of branching on the properties of poly(ethylene terephthalate) fibers

“…The existence of branched macromolecules after the addition of a polyfunctional modifier can be seen indirectly (e.g., in a broader molecular weight distribution). 7,13 However, published systematic studies on the behavior of branched PET macromolecules in melt or solution and on the effect of branching on properties of fibers spun at different wind-up speeds are scarce. In this work, we will investigate PET modified by TMP.…”

Influence of branching on the properties of poly(ethylene terephthalate) fibers

“…with r being a parameter indicating the initial composition r ϭ 3n trif 3n trif ϩ 2n bif (7) where n trif is the number of initial trifunctional molecules, n bif is the number of initial bifunctional molecules, and p is the extent of reaction, which can be evaluated from the end-group analysis of the final polymer: …”

“…7,13 However, published systematic studies on the behavior of branched PET macromolecules in melt or solution and on the effect of branching on properties of fibers spun at different wind-up speeds are scarce. In this work, we will investigate PET modified by TMP.…”

Thermo‐rheological analysis of various chain extended recycled poly(ethylene terephthalate)

“…[6,8,17] From the industrial point of view, this melt processing of r-PET with chain extender is very interesting as it involves only onestep processing for getting modified r-PET with improved properties. [18][19][20][21][22][23][24][25] The main objective of the present work is to compare three promising chain extenders, PMDA, polymeric epoxide, and ethylene carbonate (EC), in their role as a compensator for reduction in chain length of r-PET during extrusion. The effects of additive loading upon melt processing and mechanical properties will also be explored herein.…”