Electromagnetic Processing Line

A method for manufacturing a film, the method having the steps creating a cast film having a polymer component, a monomer component, a nanoparticle component, a magnetic-filler component, or a combination thereof; shearing the cast film; aligning a cast-film component by applying an electric field to the cast film; aligning a cast-film component by applying a magnetic field to the cast film; curing or polymerizing a cast-film component; annealing the cast film; and evaporating solvent from the cast film

Kinetics of structural evolution during crystallization of preoriented PET as followed by dual wavelength photometric birefringence technique

A two-color laser photometric measurement system was used to follow birefringence changes in annealing of prestretched PET films. This technique was shown to be capable of detecting large retardation (and thus birefringence) changes beyond one wavelength of the light. The use of green and red lasers in the photometric system allows the detection of the reversals in birefringence during the course of annealing. Unless critical orienialion/erystallinity levels are developed by stretching the films, heat setting the films at temperatures close to glass transition temper ature results in complete elimination of preferential orientation. At Intermediate stretch ratios, crystalline regions form and Ihe acl as anchor points establishing a network for the orienied amorphous chains. These Dims exhibit partial relaxation followed by rapid increase in birefringence due to the accelerating effect of orientation on crystallization. At high stretch ratios, where substantially oriented and strain crystallized structures are obtained, the initial relaxation stage disappears and birefringence continue to increase throughout the heat setting process even at temperatures very close to glass transition temperature. In these films, however, the total change of birefringence decreases as more of the chains are oriented and crystallized in the stretching stage, leaving a smaller fraction of polymer chains to rearrange during Ihe annealing stage. The kinetics of the structural change exhibit a complex behavior and the largest rates of structural changes were observed in films exhibiting intermidiate birefringence levels

Phase Behavior of Rapidly Quenched PVDF/PMMA Blends as Characterized by Raman Spectroscopy, X-Ray Diffraction and Thermal Techniques

Although PVDF/PMMA blends have been studied extensively, the phase behavior as a function of melt quenching conditions has not been examined in detail in the past. In this paper we report our results on the isotropic blends of PVDF/PMMA quenched into ice water as well as on a casting roll set at 30°C in all composition ranges. The results confirm the miscibility of this blend for all composition ranges, although at high PVDF (∼85%) concentration micro heterogeneities were evidenced through thermal analysis. Though pure PVDF is observed to be mostly in the α crystalline form, the addition of PMMA favors the β crystal structure in composition range 85/15–60/40. Ice water quenching yields amorphous blends containing more than 40% PMMA and these films are deemed good candidates for rubbery state processes (between Tg and Tcc), including tenter frame biaxial stretching, where they can be oriented significantly at these low temperatures while undergoing strain induced crystallization

The Effect of Deformation and Composition on the Structure Evolution in the Pre-Oriented PET/PEI Blend Films during the Heat Setting Process

The objective of this research is to affect the deformation and thermal behavior PET through synergistic blending strategies. For this purpose, a series of crystallizable compositions of PET (Tg=70°C) and PEI (Tg=215°C) were prepared. The structure evolution during uniaxial deformation was investigated. The very fast structural rearrangement processes that take place during the heat setting process were investigated using the newly developed Spectral Birefringence Technique. In 100/0 PET/PEI samples, above the onset of strain hardening the birefringence rapidly increases with time. The total increase in birefringence decreases with the increased levels of orientation and crystallinity imparted during the stretching stage. The introduction of PEI and the increase of its concentration tend to dilute the crystallizable PET chains. This, in turn, introduces a relaxation step at the early stages of heat setting at 180°C even in samples that were stretched to high stretch ratios. We also demonstrated that our Spectral Birefringence Technique is fast enough to keep up with the very rapid changes that take place at 180°C where the fastest crystallization is experienced

Nanoparticle induced network self-assembly in polymer carbon black composites

A novel percolation phenomenon with inorganic nanoparticle loading in polyamide 6-carbon based nanoparticle hybrids was identified. Percolation threshold substantially shifts to lower carbon black (CB) volume fractions in the presence of optimum concentration of chemically modified montmorillonite (organoclay) while the effective organoclay concentration can be optimized to lower the slope of percolation curve maintaining electrical conductivity within static dissipative 10−6–10−9 S cm−1 range. Organoclay/CB ‘nano-unit’ morphology was found in polyamide 6 ternary hybrids. It is composed of stacked organo-montmorillonite platelets that deform to wrap partially around one or two primary CB aggregates. This elementary nano-unit structure induces CB network self-assembly within polyamide 6 matrices. The structure was found to be prevalent throughout the polymer matrix. This morphology remains robust under wide range of thermal-deformation histories due to the strong preferred organoclay/polyamide 6/CB interactions that partially blocks the electron conduction and hopping mechanisms with clay ‘walls’ thereby reducing the slope of the percolation curve. Organoclay can be used as a dispersion control agent in these polymer–carbon systems to induce self-assembly of CB network at low CB content, simultaneously, partial blocking the electron hopping pathways to level the slope of percolation curves. High order exfoliation and nano-scale dispersion of organoclay is essential to induce this advanced percolation phenomenon

Atomic force microscopy observations of the structural development during the uniaxial stretching of crosslinked low-density polyethylene in partial and fully molten states

The effect of uniaxial deformation in partially and fully molten states on the morphology of crosslinked low-density polyethylene has been investigated. At low temperatures, the morphology is predominantly fibrillar, with little kebabs appearing on the fibril surfaces. As the deformation temperature is increased into the melting range, the shish density decreases, and overgrowths of kebabs on the fibrils concurrently increase in length. This gives rise to added twisting of the kebabs reflected in the orientation factor analysis. This shish/twisted lamellar kebab texture is observed only in a partially molten state. Studies in a substantially molten state indicate the absence of shish, althugh short lamellae are observed that are oriented in the transverse direction. This morphology indicates a high chain orientation factor as a result of short lamellae that exhibit small twisting similar to Matsumura\u27s rod model. The absence of shishes in the final films stretched isothermally in a substantially molten stage agrees with Schultz\u27s model, in which imperfectly formed shishes dissolve if they are not stabilized by rapid cooling, as is the case in these studies

Nonlinear Mechanooptical Behavior of Poly (ethylene naphthalate)/Poly (ether imide) Blends. Dynamic Phase Behavior

The mechanooptical behavior and structural organization processes in melt miscible PEN−PEI blends have been investigated in the rubbery state as influenced by blend composition, stretching temperature, and deformation rate. This was accomplished using a spectral birefringence system integrated in a specially built uniaxial stretching machine1,2 where real-time birefringence, true stress, and true strain are monitored during the course of the deformation. Three distinct stress−optical regimes have been observed with an additional glassy component. The final structure and deformation behavior of the blends have been mapped out in a dynamic phase diagram showing that the material undergoes three critical structural transitions. At low temperatures near Tg the polymer remains in a nematic-like state, and orientation-induced crystallization occurs only above a certain stretching temperature. At intermediate temperatures the liquid−liquid (Tll) transition occurs wherein the material transforms from a “structured liquid” to a “true liquid” state at (1.08Tg (K)) exhibited by the disappearance of the initial glassy component as the material becomes devoid of the segmental correlations. At higher temperatures, where the relaxation process dominates and where the thermal induced crystallization is still suppressed, the material was found to remain in the amorphous state even after being stretched to large deformation levels

Stress-Optical behavior of Poly (m-xylylenediamine adipamide)(Nylon MXD6): Influence of molecular weight

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 and high rates the stress optical behavior was found to start with an initial glassy photo elastic behavior. Decreasing stretching rate or increasing processing temperature was found to eliminate this glassy photoelastic regime leading to the observation of a linear initial stress optical behavior past a temperature of 95 °C (Tll). The stress optical constant (SOC) was about the same for both M.W. materials stretched at temperatures past Tll, at 2.7 GPa−1 for HPA6 and 2.61 GPa−1 for LPA6. Following this initial regime, the behavior is controlled by the competition between orientation and relaxation during deformation. If the chain orientation relaxation is not suppressed by increasing the stretching rate and/or the molecular weight or by decreasing temperature, the material strain crystallizes