Starch is a complex branched glucose polymer whose branch molecular weight distribution (the chain-length distribution, CLD) influences nutritionally important properties such as digestion rate. Chain-stopping in starch biosynthesis is by starch branching enzyme (SBE). Site-directed mutagenesis was used to modify SBEIIa from Zea mays (mSBEIIa) to produce mutants, each differing in a single cons...

In this work, the thermo-oxidative behavior of PEKK films (~50 µm thick) in solid state were investigated. Since mechanical properties samples, especially strain at break, are clearly affected after long ageing time, modifications structure have been monitored molecular and macromolecular scales using different techniques such as gel permeation chromatography, X-Ray scattering, differential sca...

sesame (sesamum indicum l.) seed and oil have long been used widely as healthy foods to supply energy and prevent aging. some of the main active anti-oxidative constituents in sesame seeds are γ-tocopherol and phenols. the purpose of this study was to investigate the relationship between roasting temperature and time with γ-tocopherol and total phenolic compounds (tpc) of sesame seeds when roas...

Abstract The degradation of dielectric properties polypropylene (PP) at high temperature affects the operational stability metallised film capacitors. This study presents a method to improve high‐temperature performance PP through long‐chain branching modification and regulating crystalline properties. Different amounts nucleating agents were added branched (LCBPP) effect crystallisation on ele...

We analyze the onset of ‘necking’ and subsequent filament failure during the transient uniaxial elongation of viscoelastic fluid samples in extensional rheometers. In the limit of rapid elongation (such that no molecular relaxation occurs) the external work applied is all stored elastically and the Considère criterion originally developed in solid mechanics can be used to quantitatively predict...

Size exclusion chromatography (SEC, also called GPC or GFC) is the most important test method for the determination of the molecular properties of synthetic and natural macromolecules in solution. Different from traditional methods which only establish average property values, SEC allows the simple and fast determination of property distributions of macromolecules, e.g. molecular weight distrib...

Branched and crosslinked degradable polyesters based on lactic acid, lactide and εcaprolactone were prepared by utilizing different polymerization methods. Chain linking of hydroxyl telechelic lactic acid oligomers with 1,6-hexamethylene diisocyanate (HMDI) as a chain extender, yielded lactic acid based poly(ester-urethanes). When an excess of HMDI was used, polymers with broader molecular weig...

The introduction of long-chain branched structures into biodegradable polyesters can effectively improve the melt strength and blow-molding properties polyesters. In this study, pentaerythritol (PER) was used as a branching agent to synthesize poly(butylene dodecanedioate) (PBD), resulting polymers were characterized by Nuclear Magnetic Resonance Proton Spectra (1H NMR) Fourier Transform Infrar...