Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 47 for “"Polymer processing"”.
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Elongational Flows in Polymer Processing
The production of long, thin polymeric fibers is a main objective of the textile industry. Melt-spinning is a particularly simple and effective technique. In this work, we shall discuss the equations of melt-spinning in viscous and viscoelastic flow. These quasilinear hyperbolic equations model the …
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Primary fabrication methods and costs in polymer processing for automotive applications
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1983.
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A Metamodel based Multiple Criteria Optimization via Simulation Method for Polymer Processing
<p>Polymers have been gradually replacing metals in many applications due to their versatility. Nowadays, many consumer products such as computers and automobile components rely on the technology and production from polymer companies. To ensure the sustainability of these companies, it is important …
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Development of analytical systems and monitoring of VOCs emissions during polymer processing
… (VOCs) emissions during thermal degradation of polymers. This was used to estimate organic emissions from both virgin polymer resins and commingled plastics. The effects of process parameters, i. e., temperature, heating rate and residence time, were also studied. Significant VOCs emissions were …
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Microcellular polymer processing and the design of a continuous sheet processing system
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.
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Multi-scale modelling describing thermal behaviour of polymeric materials. Scalable lattice-Boltzmann models based upon the theory of Grmela towards refined thermal performance prediction of polymeric materials at micro and nano scales.
… into the fundamental mathematics behind polymer heat transfer and associated processes. The aim is to derive models for polymer dynamics, especially heat dynamics, that are considerably less approximate than the ones used at present, and to translate this into simulation and optimisation …
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Moment analysis methods of ultrasonic waveforms to characterize the internal temperature and melt transition boundary for materials with irregular porosity.
… interest to the petro-chemical, food, and polymer processing industries, and ultrasound has found limited investigation within the literature for such applications. In this thesis, ultrasound is shown to be useful for monitoring spatial thermal variations through the thickness of a material …
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Polymer blends formed by the solid state mechanical alloying process
In the early 1970's a new processing technique to produce metallic alloys was developed by Benjamin and co-workers. This novel technique, called Mechanical Alloying (MA), involves the repeated welding, working hardening, and fracture of metallic powders to form an alloy. The research presented in …
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An Investigation of the Microstructure and Properties of a Cryogenically Mechanically Alloyed Polycarbonate-Poly(Ether Ether Ketone) System
This work investigates processing-microstructure-property relationships of a model cryogenically mechanically alloyed polymer-polymer system: polycarbonate (PC) and poly (ether ether ketone) (PEEK). Mechanically milled and alloyed powders were characterized using a variety of techniques including …
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A reactive melt modification of polyethylene terephthalate
… rheological properties suitable for certain polymer processing operations such as extrusion blow molding or extrusion foaming to low densities. Among five different low MW difunctional and trifunctional epoxy compounds, triglycidyl isocyanurate is shown to be an efficient reactive melt …
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The kinetics of drug dissolution in polymers during hot-melt extrusion
… important and widely used continuous process in polymer processing for over one hundred and fifty years. However, it has only been recently applied and adopted by the pharmaceutical industry to prepare solid oral dosage formulations with increased bioavailability for the poorly-water soluble …
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Molecular simulation of crystal growth in alkane and polyethylene melts
… powerful tool for understanding the process of polymer crystallization. By using carefully constructed simulations, one can independently observe the two phenomena responsible for melt crystallization: nucleation and growth. This research focuses on modeling the growth process using potentials …
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Single molecule studies of flexible polymer systems
Polymeric materials play a profound role in our daily lives. There have been many key advances in polymer processing over the last several decades, but much of the underlying molecular behavior and physics of polymer solutions is not fully understood. Single molecule studies of polymer solutions …
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Design of Multilayer Optical Media: Organic Photovoltaics and Optical Data Storage
… magnetic hard drive disks. Using scalable polymer processing techniques, it is possible to fabricate a multilayer optical data storage medium that satisfies the need for low-cost, scalable storage capacity. With a large number of physical layers, only small changes are needed to optical …
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Synthesis and evaluation of novel polymer modifiers for biodegradable polymers
The effects of ester plasticizers and copolymers on the mechanical properties of the natural biodegradable polymers, poly(3-hydroxybutyrate) [PHB] and poly(lactic acid) [PLA] have been studied after subjecting to melt processing conditions. Ester plasticizers were synthesized from citric, tartaric …
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Coupling molecular conformation to polymer chemistry and composition via flow
There has been extensive study on the behavior of polymers in the presence of fluid flow over the past century. There remain, however, fundamental questions about how flows couple to molecular degrees of freedom and vice versa. This pressing problem has profound implications in polymer processing …
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Development of biodegradable microfluidic networks for tissue engineering
… soft lithography, and traditional polymer processing are combined to develop a fully biodegradable microfabrication platform using poly(DL-lactic-co-glycolic) acid (PLGA 85:15). First, micron scale structures fabricated on silicon substrates are transferred into the surface of …
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A large-deformation thermo-mechanically coupled elastic-viscoplastic theory for amorphous polymers : modeling of micro-scale forming and the shape memory phenomenon
Amorphous polymers are important engineering materials; however, their nonlinear, strongly temperature- and rate-dependent elastic-viscoplastic behavior is still not very well understood, and is modeled by existing constitutive theories with varying degrees of success. There is no generally agreed …
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