Digital Commons Network^™

High-Energy, Curable Polycyclopentadiene Binder For Solid Rocket Propellants, Jian Guo Ning

Theses

Diels Alder polymerization of cyclopentadiene ( CPD ) has been carried out at 170°C under inert atmosphere. The resulted polymer has a low bulk viscosity, 7.4 cps, and a number average molecular weight M_n up to 3000. This liquid Prepolymer is curable with maleic anhydride. With ammonium perchlorate, aluminum, and maleic anhydride, a high energy solid propellant has been formulated with this polymer. Via bomb calorimeter, Instron, and density measurement, it was found that this propellant has a better heat of combustion, tensile strength, and solid loading than that of the commercial rocket propellant based on hydroxyl terminated polybutadiene.

Particle Size Distribution In Isothermal Batch Emulsion Polymerization, Bhavin R. Patel

Theses

A detailed modified mathematical model for particle size distribution in isothermal batch emulsion polymerization of Styrene and Vinyl acetate is proposed on the basis of the population balance approach in presence of several kinetic and mass transfer processes. This study is limited to Smith-Ewart's case II, which assumes instantaneous free radical termination within the polymer particles. Radical desor¬ption mechanism from polymer particles is included in the model and the desorption rate is formulated from the diffu¬sion theory which suggests that the rate co-efficient should be inversely proportional to the surface area of polymer particles.

Experimental runs are made using laser …

The Kinetics And Mechanism Studies Of Cathodic Electro-Initiated Crosslinking Polymerization Of Unsaturated Polyester Prepolymer, Joseph Yuan-Ji Sheng

Theses

The cathodic electro-initiated polymerization reaction of the unsaturated polyester prepolymer has been found to have the characteristics of the first order ionic initiation polymerization mechanism. The rate of polymer formation is directly proportional to the current intensity and voltage supplied, but inversely proportional to the reaction temperature. The rate of initiation can be expressed as a function of the initial concentration of the prepolymer, residence time and reaction temperature. The rate expression of the initiation step has been derived based upon the experimental data collected as follows:

ln W = k0 exp[-Ea/RT] Ca0 ln t + ln b

where k0 …

The Kinetics And Mechanism Studies Of A Polymer Powder Coating On Metal Surface By Cathodic Electrodeposition Process, Wen-Lin Wu

Theses

A polymer dispersion of fluorocarbon with solid constent in the range of 10-25% were prepared from white powder polytetrafluorethylene (PTFE), emulsifier combination of dodecylbenzyldimetlyl sulfonium chloride and Trition N-150, and other components or additives. Such a fluorocarbon dispersion is very stable against coagulation and has a pH in the range of 8-10, which is especially suitable for powder coating purpose.

A new electrocoating technique, which is called cathodic electrodeposition powder coating method, was conducted in this study. This new coating method includes four steps: pretreatment, electrocoating, drying and baking. Two kinds of degreased metal substrates, aluminum and steel plates, were …

Preparation And Properties Of Novel Dental Adhesives Based Upon Pentaerythritol, Yuan-Yuan Su

Theses

Urethane methacrylates were synthesized from Pentaerythritol, TDI, HEMA and four phenolic blocking agents or from hydroxypropyl methacrylatel TDI and two phenolic blocking agents. All the products were characterized by melting pointy infrared spectroscopy, NMR spectra, and elemental analysis. The bonding of these materials to dentin slices was also investigated. Such materials are supposed to not only react with the organic constituent of dentin but also polymerized with restorative resin. It was found that bond strength was enhanced by the use of the urethane methacrylates, resulting in best mean bonding strengths of 2400 psi.

An Experimental Investigation Of The Kinetics And Thermal Properties Of Poly(Ethylene) Terephthalate And Its Related Di-Acid Modified Copolymers, Satish Baliga

Theses

Poly(ethylene) Terephthalate , PET, is synthesized from purified Bis-hydroxyethyl Terephthalate,(BHET), in the presence of antimony oxide catalyst. Rate constant for the polycondensation reaction, based on a second order kinetic model is found to be 152.4/mol/hr.

A new modified polyester Polyethylene Adipic Terephthalate (PEAT) is synthesized from BHET and adipic acid. The effect of adipic acid content in the copolymer,on the rate of polycondensation is studied. Adipic acid is shown to improve the activity of the polymer chain ends thereby increasing the apparent reaction rate constants.

The modified polyesters are observed to melt at a lower temperature than PET. Moreover, the …

Stability Of Bicomponet Polymeric Liquids In Poiseuille Flow, Chin-Chang Jeng

Theses

Polymer processing, involving two or more components, has become more popular recently in industrial plants. However, product Quality is affected very much by the fluid stability. Some theoretical and experimental results concerning Newtonian and non-Newtonian flow in rectangular coordinates, have been published, and the fluid-fluid interfaces were observed to be unstable by some researchers.

In this paper, the linear stability of bicomponent non-Newtonian fluids flowing in a cylindrical tube was investigated by using the Ellis model. Only the very long wave and the axisymmetric disturbances were considered. The Ellis zero-shear-rate viscosity ratio, m( = η02 / η01 )destabilizing. The half-zero-shear-rate-viscosity …

Transient Phenomena Of Polymer Solutions, Nikolaus Zwetkow

Theses

With the aid of a rotational viscometer, several transient phenomena were studied with different polymer solutions. In order to be acquainted with the operations of the rotational viscometer, viscosity measurements were made on polystyrene solution of a 7.14 wt. % NBS-2-35967 in a 35 - 65 mixture of aroclor and TCP, polyisobutylene (16.5% in mineral spirits), Indopol H-1900 (polyisobutylene) and 4.5% polyisobutylene in Primol 355. All these were done at a temperature of 77°F, except for Indopol H-1900 which was done at different temperatures. The results are listed in the section of tables and graphs.

Viscosity was measured with a …

Effect Of Mixing On Polymerizations In Batch Reactors, John Guy Steenrod

Theses

The effects of mixing on polymerizations in batch reactors are examined theoretically for initiations by thermal decomposition of catalyst and by absorption of ionizing radiation. Mathematical expressions for predicting the first three moments of the dead polymer size distribution are presented. Two extreme mixing states. perfect and no mixing. are considered. It is shown that in batch reactors mixing in any direction in which nonuniform initiations exist increases the polymerization reaction rate and the number average molecular weight, and decreases the weight average and the polydispersity.

Experimentally, the effects of mixing were studied in a solution polymerization system, in a …

Flow Behavior Of Molten Polymer Blends, Kryspin Pawel Maciejewski

Theses

An experimental study of molten polymer blends was made using the Instron Capillary Rheometer. The materials investigated were two phase blends of non-crystalline polymers (poIymethylmethacrystate-low Mw-polyvinylacetate, polyvinylacetate-polystyrene, polymethylmethacrylate-low Mw-polystyrene, polymethylmethacrylate-high Mw-polystyrene), crystalline polymers (polyethylene-polypropylene) and combinations of non-crystalline-crystalline polymers (polyethylene-polystyrene). Two methods of sample preparation were used, blending of a polymer pair in a molten state by the use of Brabender blender, and a simple manual blending of pellets in desired proportion. The Brabender blended polymer pairs show lower viscosities, this is interpreted molecularly as a result of a reduction of the amount of chain entanglement on shearing of the …

Continuous Interfacial Polycondensation Of Nylon 6-6, Chandrakant A. Patel

Theses

Nylon 6-6 has been prepared by continuous interfacial polycondensation from hexamethylene diamine and adipyl chloride in a stirred system. The effect of monomer concentration and stirring on the intrinsic viscosity of polyamide 6-6 solution in formic acid (90%) was determined.

As stirring rate and monomer ratio increased, the intrinsic viscosity and polymer yield went through a maximum. Diffusion coefficient (D_AB) for hexamethylene diamine was calculated and from that J_D and mass transfer coefficient /D_AB were calculated. A relation between Reynolds number and J_D factor was established by correlation curve.

Dielectric Properties Of Atactic And Isotactic Polystyrene, Thaddeus F. Kroplinski

Theses

The purpose of this investigation was to determine the dielectric constant and dissipation factor of atactic and isotactic polystyrene at 25°C and at frequencies of 0.1, 1.0, 10, and 100 kilocycles per second. In addition, the effects of molecular weight and crystallinity on the dielectric properties of polystyrene mos also studied.

Polystyrene slabs of uniform thickness mere prepared by molding the polymer under heat and pressure. The isotactic polystyrene slabs Imre annealed at 175°g for various lengths of time to achieve varying degrees of crystallinity.

The molded polystyrene slabs were fitted with circular aluminum foil electrodes to form a three …

Viscoelastic Properties Of Polymer Melts, Wu-Shiong Lee

Theses

Thirteen samples of molten polymers were used to test Spriggs and Careau Models. Two empirical equations, one for apparent viscosity and the other which is new, for primary normal stress difference, were checked with these samples also.

In order to test the models, material functions were sought for some specific flow patterns under which the experimental data were collected, and then these functions were compared with data.

Careau Model was found to be better than Spriggs Model in representing molten polymer properties but still yield large deviations. Two empirical equations fitted data quite well and were expected to be useful …

The Effect Of Polymerization Variables On Reaction Rate And Intrinsic Viscosity, David H. Smith

Theses

The free radical solution polymerization of vinyl acetate in benzene was studied under simulated commercial conditions. The effects of monomer, initiator, inhibitor, and chain transfer agent concentration on the reaction rate and intrinsic viscosity were examined. The initial reaction rates with monomer concentrations from 40% to 70% and AIBN concentrations from 0.2% to 0.5% were in agreement with the kinetic equation, - d[M]/dT = K[M]² [I]^1/2. After the initial reaction there was an increase in the reaction rate apparently associated with high viscosities, which is consistent with the Trommsdorff effect. The addition of hundredths of a percent …

Fluid Friction Reduction By Water Soluble Linear High Polymers, Arthur Edward Davis

Theses

The effects of various dilute aqueous linear high polymer solutions on turbulent pipe flow were studied to determine the polymer most suitable for testing as the drag reducing component in the proposed coating. Results of this study are presented for commercial schedule 40 1/4 inch NPS black iron pipe. Tests were conducted at Reynolds numbers of 6.2x10⁴,8.3x10⁴ and 9.8x10⁴.

Attempts were made to prepare a coating containing a friction drag reducing polymer - Polyhall 295 polyacrylamide - utilizing various techniques of polymer incorporation into the paint including several grinding and dispersion methods, adding the polymer …

The Plasticization Of 4-Methyl-Pentene-1 (Tpx-Rt-D30) Polymer With Petroleum Jelly, Joseph P. Mccann

Theses

The properties of TPX-RT-D30 (4-methyl-pentene-1 polymer) have been changed by blending petroleum jelly with the polymer. The polymer was blended in a Brabender apparatus with up to 40% by weight petroleum jelly (P.J.) at 270°C, pressed and quenched in water. Samples were die cut for the various tests. The polymer tensile properties (ASTM-638-64T) showed both a break and yield value in all ratios as compared to only a break value for the TPX-RT polymer. Breaking strength ranged from 4000 psi for pure TPX-RT down to 1000 psi at 40% P.J., with a leveling point of 2000 psi at 15% P.J. …

Viscosity Determination During Polymerization, Elmer David Jones

Theses

This project was undertaken for the purpose of designing, constructing, and operating a viscometer which could be employed for measuring viscosities in the range of 200 to 700 poises at temperatures up to 300°C. Such an instrument was built and used to study the viscosity of Type EV polymer during polymerization.

The new viscometer is based cm the principle of concentric rotating cylinders. It is unique in that it can be suspended directly in a polymer batch and will operate under temperature and viscosity conditions as outlined above. Polymerization curves for batches studied show that the instrument gives viscosity values …