The Mark–Houwink–Sakurada (MHS) equation allows for estimation of rheological properties, if the molecular weight is known along with good understanding of the polymer conformation. The intrinsic viscosity of a polymer solution is related to the polymer molecular weight according to the MHS equation, where the value of the constants is related to the specific solvent and its concentration. Howe...

Small interfering RNA silences specific genes by interfering with mRNA translation, and acts to modulate or inhibit specific biological pathways; a therapy that holds great promise in the cure of many diseases. However, the naked small interfering RNA is susceptible to degradation by plasma and tissue nucleases and due to its negative charge unable to cross the cell membrane. Here we report a n...

Highly porous composites scaffolds of poly-D,L-lactide (PDLLA) and poly(lactide-co-glycolide) (PLGA) containing different amounts (10, 25 and 50wt%) of bioactive glass (45S5 bioglass) were prepared by thermally induced solid-liquid phase separation (TIPS) and subsequent solvent sublimation. The addition of increasing amounts of bioglass into the polymer foams decreased the pore volume. Converse...

This work involves the degradation of plastic waste in the presence of three different nanocatalysts. A thin film of LLDPE was formed with all three nanocatalysts separately in the solvent. Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetric (DSC) analysis of polymers suggest that the presence of these catalysts lowers the degradation temperature and the change mechanism of...

This thesis presents different analytical strategies for the study of the degradation of synthetic polymers. Particular attention was given to the mechanisms involved at the beginning of the polymer breakdown. Three model polymers were used in order to assess different degradation rates. The first polymer studied was a stabilised polyether: Poly(ethylene oxide-propylene oxideethylene oxide) tri...

1. The walls of Micrococcus sp. A1contain about 43% of a phosphorylated polymer. It was extracted with cold trichloroacetic acid and purified by chromatography on DEAE-cellulose. 2. The polymer contained equimolar amounts of d-glucose, N-acetylgalactosamine and phosphate, and was readily hydrolysed under gentle acidic conditions to a phosphorylated disaccharide. 3. Chemical and enzymic degradat...

This study was aimed at assessing the potential use of electrospun fibers as drug delivery vehicles with focus on the different diameters and drug contents to control drug release and polymer fiber degradation. A drug-loaded solvent-casting polymer film was made with an average thickness of 100 microm for comparative purposes. DSC analysis indicated that electrospun fibers had a lower T(g) but ...

polyethylene is a synthetic polymer which is used in our daily life for different purposes. increased use of polyethylene causes severe environmental problems. there are different methods to decrease problem caused by polyethylene for example source reduction, incineration and land filling and all of them have their own drawbacks. so, the best way to reduce the problem caused by polyethylene is...

The thermal stability of polyethylene oxide (PEO) in sustained release tablets prepared by hot-melt extrusion was investigated. The weight average molecular weight of the polymer was studied using gel permeation chromatography. The chemical stability of PEO was found to be dependent on both the storage and processing temperature, and the molecular weight of the polymer. Storage of the polymer a...

Polymer degradation and drug release kinetics from PLGA microspheres were investigated under neutral and acidic pH conditions. Two different Mw formulations (Mw: 25,000 and 70,000) were investigated and both exhibited a triphasic release profile at pH 7.4 as well as at pH 2.4. The initial burst and lag phases were similar for both pH values, while the secondary apparent-zero-order phase was sub...