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The drying behavior of blade casting aqueous chitosan solution was investigated by means of a custom designed real time characterization system that can track the thickness, weight, temperature and in-plane and out-of-plane birefringence. Beyond a critical solvent concentration, initially isotropic cast solution rapidly develops optical anisotropy as detected by out of plane birefringence measurement...
The effect of blend composition and deformation history on the development of structural hierarchy in crystallizable PET rich blends of PET/PEI from amorphous precursors was investigated. PET/PEI films are melt miscible consequently the addition of PEI to PET increases the glass transition temperature while slightly broadening it as a result of partial micro phase separation. The crystallization in...
In order to have a fundamental understanding of the temporal evolution of physical characteristics of Polyetherimide (PEI) film and processing parameters, real time measurements are essential. Because drying and stretching processes of solvent-cast polymer film are complex, off line measurements are unable to reveal the temporally varying detailed information, especially for fast “transient events”...
In this paper, we investigate film drying followed by mechano-optical behavior of PVA films in solid and swollen state, respectively. During drying the real time evolution of thickness, weight, and birefringence (both in and out of plane) are captured using a highly instrumented measurement system. During drying, initially isotropic solution rapidly loses water and beyond a critical stage it develops...
Multiple overlapping physical and chemical changes often take place during casting/drying and imidization from PMDA-ODA polyamic acid precursors from cast solutions. To shed light into details of these complex phenomena, we designed a unique real time measurement system that combines true stress, true strain, in-plane birefringence and temperature with polarized ultra-rapid scan FT-IR spectrometry...
The main focus of this research is to identify the structural mechanisms that are responsible for changes observed in various stages of coupled mechano-optical (stress and strain optical) relationships as they are influenced by the deformation mode, level and rate. This involves in situ real time studies of the true-stress-strain-birefringence of sequential biaxially stretched PET films using a highly...
Multifunctional single and triple-layer films exhibiting flexibility, enhanced modulus and gas barrier properties were developed using a soluble polyamide-imide (PAI) in dimethylacetamide (DMAc) with ammonium-modified montmorillonite (MMT, Cloisite 30B) mineral clay. The drying behavior and associated anisotropy development were determined real-time, using a newly developed real-time measurement system...
We present an experimental study of real time true stress–strain–birefringence measurements to elucidate the sequence of structural mechanisms that occur during simultaneous biaxial stretching of PET films from amorphous precursors in rubbery state. Stress–birefringence relationship, wide angle X-ray diffraction, Raman spectroscopy and DSC thermal analysis were used to identify the stages of the mechano-optical...
The effect of molecular weight and rubbery state uniaxial stretching conditions on the mechano-optical behavior of Poly(m-xylylenediamine adipamide) (Nylon MXD6) films was investigated using a real time spectral birefringence stretching machine. The stress optical behavior exhibits a multi stage behavior that depends on process conditions as well as molecular weight. At low stretching temperatures...
The influence of platelet-type clay nanoparticle (nanoplatelet) on the structural evolution in injection-molded nylon 6)/carbon composites was investigated. In the absence of nanoplatelets, the nylon 6/CB systems were found to exhibit unoriented structure with nylon 6 crystalline regions exhibiting exclusively α crystal form throughout the thickness of the samples. However, inclusion of nanoplatelets...
The effects of TiO 2 particles on the crystallization and uniaxial stress–strain behavior of poly(ethyleneterephthalate) (PET) films from amorphous precursors were investigated. The addition of small fraction of sub micron sized TiO 2 particles were found to suppress the mechanical relaxation processes associated with high temperature side of the β relaxation while enhancing the low...
Our main focus in this study is to investigate the deformation behavior of PP in temperature range where the PP is partially molten using a newly developed uniaxial stretching system. This system allows the real time study of the structural reorganization processes as reflected in birefringence coupled with true stress and true strain at temperature and deformation rates used in industrial film process...
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