نتایج جستجو برای: polymer degradation

تعداد نتایج: 240989  

Journal: :Analytical chemistry 2001
M Vazquez D Schmalzing P Matsudaira D Ehrlich G McKinley

Electrophoretic channels are filled with a polymer matrix prior to their use in DNA separations. This process, called gel-loading, can be accomplished manually, using syringes, or can be automated through the use of small pumps or vacuum. The injection rate is constrained by the desire to minimize shear-induced degradation of the polymer molecules. Currently, the community lacks quantitative da...

Journal: :Acta biomaterialia 2010
Robert B Metter Jamie L Ifkovits Kevin Hou Ludovic Vincent Benjamin Hsu Louis Wang Robert L Mauck Jason A Burdick

The properties of electrospun fibrous scaffolds, including degradation, mechanics and cellular interactions, are important for their use in tissue engineering applications. Although some diversity has been obtained previously in fibrous scaffolds, optimization of scaffold properties relies on iterative techniques in both polymer synthesis and processing. Here, we electrospun candidates from a c...

2012
Ryan D. McCormick Jeremy Lenhardt Adrienne D. Stiff-Roberts

The molecular weight of a polymer determines key optoelectronic device characteristics, such as internal morphology and charge transport. Therefore, it is important to ensure that polymer deposition techniques do not significantly alter the native polymer molecular weight. This work addresses polymers deposited by resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE). By using ...

2012
M. Shahidul Islam

Ageing and degradation has been accomplished on Microstructured Polymer Optical Fiber (MPOF) by changing simulated ambient environmental condition to ascertain their suitability in possible automotive application. Both single Moded Microstructured Polymer Optical Fiber (SM-MPOF) and Graded Index Microstructured Polymer Optical Fiber (GI-MPOF) has been studied for physical ageing and chemical de...

2015
Mayura Oak Rhishikesh Mandke Sushant Lakkadwala Lindsey Lipp Jagdish Singh Cyrille Boyer

The purpose of this study was to investigate the effects of size and type of incorporated model molecules on the polymer degradation and release profile from thermosensitive triblock copolymer based controlled delivery systems. In vitro release of the incorporated molecules demonstrated slow release for risperidone (molecular weight (Mw) = 410.48 Da; partition coefficient (Ko/w) = 3.49), while ...

2013
S. Mehta Satya S. Shivkumar

The thermal degradation of foamed polymethyl methacrylate (PMMA) patterns in the expendable pattern casting process has been studied. Various physical transitions that may occur during the degradation of PMMA have been determined using scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis, and the effects of polymer density on the degradation characteri...

2017
Milica Stanković Christine Hiemstra Hans de Waard Johan Zuidema Rob Steendam Henderik W. Frijlink Wouter L.J. Hinrichs

In this study, novel hydrophilic multiblock copolymers composed of semi-crystalline poly(ε-caprolactone) [PCL] blocks and amorphous blocks consisting of poly(D,Llactide) (PDLA) and poly(ethylene glycol) (PEG) [PDLA-PEG] were synthesized. The block ratio of these [PDLA-PEG]-b-[PCL] multiblock copolymers was varied and the degradation of implants prepared of these polymers by hot melt extrusion (...

2008
Benjamin J. McCoy

zC C 4 Z' ;e: : ; ; " f fL-3 =A "Polymer degradation occurs when polymer ciains are broken under the influence of 3= 2; J:

Journal: :Environmental science. Processes & impacts 2015
Berit Gewert Merle M Plassmann Matthew MacLeod

Each year vast amounts of plastic are produced worldwide. When released to the environment, plastics accumulate, and plastic debris in the world's oceans is of particular environmental concern. More than 60% of all floating debris in the oceans is plastic and amounts are increasing each year. Plastic polymers in the marine environment are exposed to sunlight, oxidants and physical stress, and o...

Journal: :Journal of pharmaceutical sciences 2004
Amy G Ding Steven P Schwendeman

Determination of the kinetics of water-soluble degradation products inside poly(lactide-co-glycolide) (PLGA) delivery systems during polymer degradation is important to evaluate the polymer microclimate conditions, particularly microclimate pH changes for optimization of encapsulated drug stability. A pre-derivatization high-performance liquid chromatography (HPLC) method was developed for sepa...

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