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Hydrolytic degradation ability is an intriguing characteristic of poly(l-lactide) (PLLA) and it has been intensively investigated recently. However, the microstructure evolution of PLLA during the early stage of the hydrolytic degradation process is neglected. In this work, amorphous PLLA was hydrolyzed in alkaline media at temperatures from 40 to 60 °C. The variations of weight loss and molecular...
Triplet and singlet excitation energy transfer processes are investigated in two novel di- and hexa-functionalised ruthenium centred polymers prepared by RAFT methods. The polymers consist of a ruthenium trisbipyridyl ligand complex (Ru(bpy) 3 ) core and pendant polymer ‘arms’ of 9,10-diphenylanthracene (DPA). Steady state and transient emission and absorption experiments are used to investigate...
Polyimide-silica membranes are interesting hybrid architectures that possess excellent mechanical, thermal and chemical properties. However, the dispersion of inorganic domains in the polymer matrix and the compatibility between the organic and inorganic phases are critical factors in these hybrid systems, due to the lack of favorable interactions between the hydrophobic polymer and hydrophilic silica...
Copolyester was synthesized and characterized as having 94.4mol% ethylene succinate units and 5.6mol% trimethylene succinate units in a random sequence as revealed by NMR. Differential scanning calorimeter (DSC) was used to investigate the isothermal crystallization kinetics of this copolyester in the temperature range (T c ) from 30 to 80°C. The melting behavior after isothermal crystallization...
A copolyester was characterized to have 91mol% trimethylene terephthalate unit and 9mol% ethylene terephthalate unit in a random sequence by using 13 C NMR. Differential scanning calorimeter (DSC) was used to investigate the isothermal crystallization kinetics in the temperature range (T c ) from 180 to 207°C. The melting behavior after isothermal crystallization was studied by using...
A new series of sulfide-containing polyfluorene homopolymers and copolymers (PFS, PF1, PF3 and PF4) comprising 9,9-di[11-(decylsulfanyl)undecyl] fluorene, 9,9-dihexylfluorene, triphenylamine or benzothiadiazole moieties were synthesized by Ni(0)-mediated Yamamoto-coupling and palladium-catalyzed Suzuki polymerizations. Three other polyfluorenes (PF2, PF5 and PFC6) without sulfur atom in the alkyl side...
The compositions of a series of copolyesters of ethylene- and trimethylene- terephthalate were determined by NMR. The values of randomness parameter revealed these copolyesters were random copolymers with average-number sequence lengths varied from 1 to 10. These copolyesters were investigated using temperature-modulated differential scanning calorimeter (TMDSC) and wide angle X-ray diffractometer...
Crystallization kinetics and melting behavior of poly(ether ether ketone) were studied by differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC). The isothermal crystallization was performed between 290 and 320 °C. The Avrami exponents and the level off time were determined from the Avrami analysis. The minimum induction time required for the occurrence of double melting peaks...
Homogeneous atom transfer radical polymerization of methyl methacrylate (MMA) under microwave irradiation (MI) with low concentration of initiating system [ethyl 2-bromobutyrate (EBB)/CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)] was successfully carried out in N,N-dimethylformamide (DMF) at 69°C. Plots of ln ([M] 0 /[M]) vs. time and molecular weight evolution vs. conversion showed...
Three series of polydiphenylsiloxane (PDPS)-containing diblock copolymers were synthesized with controlled molecular weight and composition by sequential addition of the corresponding comonomers through a living anionic polymerization. These copolymers included poly(diphenylsiloxane-b-dimethylsiloxane) (PDPS/PDMS), poly(diphenylsiloxane-b-methylphenylsiloxane) (PDPS/PMPS), and poly(diphenylsiloxane-b-methyltrifluoropropylsiloxane)...
Fully transcrystalline, fully spherulitic specimens, and single Kevlar fiber microcomposites were prepared for isotactic polypropylene (iPP) resin with positive, negative, or mixed birefringence and annealed condition. The micromorphologic observation (PLM, PCLM, SEM, AFM) and supermolecular structure study (WAXS, SAXS) show that the optical birefringence change of iPP is related to the contribution...
The aim of this study was to evaluate the transcrystalline effect on the interfacial shear strength in a single carbon fibre (CF) reinforced syndiotactic and isotactic polypropylene (sPP, iPP) composites by the fragmentation test. It was established that the sPP matrix exhibited a very good interfacial bonding with high-tenacity (HT) CF. The interfacial adhesion was enhanced further by transcrystalline...
The micromorphologic features of sheared isotactic polypropylene (iPP) in the vicinity of fibre were investigated through polarized light microscopy (PLM), phase contrast optical microscopy (PCLM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicate that the polymorphic structures and their boundary lines can be explained from a modified model by combining the...
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