Ronald Lamonte - Academia.edu (original) (raw)

Papers by Ronald Lamonte

Research paper thumbnail of Uses and processing of cyclic olefin copolymers

Plastics Engineering, 2000

Research paper thumbnail of Cyclic olefin copolymers

Advanced Materials & Processes, 2001

... applications COC may be combined with polyethylene (PE) in monolayer blend films or used in m... more ... applications COC may be combined with polyethylene (PE) in monolayer blend films or used in multilayer films in flexible packaging for food ... When incorporated in the heat-seal layer of bags or stand-up pouches, they can improve hot-tack and ultimate seal strength without ...

Research paper thumbnail of A process for producing microfiber webs containing cycloolefin

The invention relates to a method of producing microfiber nonwovens that contain at least one cyc... more The invention relates to a method of producing microfiber nonwovens that contain at least one cycloolefin polymer by means of a melt-blow method. The invention also relates to articles produced according to this method and to their use.

Research paper thumbnail of Production of poly(arylate) using non-solvent

PURPOSE: To provide a producing method of a polyarylate by which a polyarylate of an improved col... more PURPOSE: To provide a producing method of a polyarylate by which a polyarylate of an improved color is formed, and in which a diluent can be easily separated from the polyarylate and reaction products. CONSTITUTION: A polyarylate is produced by reacting a mixture of a diester of dihydric phenol, at least one kind of aromatic dicarboxylic acid, and an inert diluent comprising a poly(-fluorinated alkylene oxide). COPYRIGHT: (C)1994,JPO

Research paper thumbnail of Preparation of poly(arylate) using a non-solvent

Research paper thumbnail of Preparation of polyarylate of improved color with cobalt salt

Research paper thumbnail of A study of polymer melt flow instabilities in extrusion

Polymer Engineering and Science, 1971

An experimental study is carried out to elucidate the melt fracture mechanism. For the study, the... more An experimental study is carried out to elucidate the melt fracture mechanism. For the study, the electrical outputs of the melt pressure transducers, mounted on the wall of a circular tube, are recorded on a Sanborn recording system. It has been observed from this study that the wall pressures start to fluctuate prior to the inception of visible melt fracture. The frequency and amplitude of the excursion signals are increased as the shear rate is increased up to and beyond the critical value. This behavior has been observed for three polymer samples tested: polystyrene, high density polyethylene, and low density polyethylene. The fluctuations of wall pressures are interpreted as due to an irregular flow of polymer melts at the tube wall. It is further investigated to find the effects of the die entry angle of a capillary, and capillary length-to-diameter ratio on the critical shear rate. A correlation between exit pressure and shear stress has been found for polystyrene and low density polyethylene. It is found that at and above the critical stress, the exit pressure increases abruptly. This is interpreted to be a sudden change in the elastic properties of the materials above melt fracture since Han et a1 have shown that the exit pressure is a measure of the elastic properties.

Research paper thumbnail of Melt flow instabilities in capillary flow of two‐phase polymer systems

Polymer Engineering & Science, 1972

An experimental study was made of melt flow instabilities in extrusion of two‐phase polymer syste... more An experimental study was made of melt flow instabilities in extrusion of two‐phase polymer systems. For the study, blends were prepared from two polymers: polystyrene (Dow Chemical STYRON 686) and high density polyethylene (Union Carbide DMDJ 4309). The experimental technique used in the present study was the same as that described in a previous paper by the authors. The study shows that there are abrupt increases both in exit pressure and in the recoverable shear strain (defined as the ratio of the exit pressure to shear stress) at the critical flow conditions. It has also been found that an addition of a small amount of high density polythylene (2.5 wt‐% and 5.0 wt‐%) increases the critical shear rate of polystyrene and hence results in a higher throughput rate before extrudate distortion is actually observed. This result is explained in terms of the independently determined melt elasticity of the two‐phase systems investigated.

Research paper thumbnail of Studies on Melt Spinning. I. Effect of Molecular Structure and Molecular Weight Distribution on Elongational Viscosity

Transactions of the Society of Rheology, 1972

A melt spinning experiment has been carried out to correlate spinning variables with the molecula... more A melt spinning experiment has been carried out to correlate spinning variables with the molecular weight, molecular weight distribution, and long chain branching of the polymer being spun. Materials chosen for study were three high density polyethylenes having widely different molecular weight distributions, a low density polyethylene having much long chain branching, a polystyrene, and a polypropylene. Molecular characteristics and rheological properties of the materials in simple shearing flow had been independently determined. For the study, a bench scale, melt spinning apparatus was built, and measurements were taken of thread tensions at the take-up device. The axial profiles of thread diameter were measured by a photographic technique. The molten fibers traveled through a heated chamber maintained at the same temperature as the melt. These measurements were then used to determine the elongational viscosity in the absence of any temperature effect.

Research paper thumbnail of Crystallization, melting, and relaxation of modified poly(phenylene sulfide). II. Dynamic relaxation characteristics

Journal of Macromolecular Science, Part B, 1996

Page 1. J. MACROMOL. SC1.-PHYS., B35(2), 179-197 (1996) Crystallization, Melting, and Relaxation ... more Page 1. J. MACROMOL. SC1.-PHYS., B35(2), 179-197 (1996) Crystallization, Melting, and Relaxation of Modified Poly(pheny1ene sulfide). II. Dynamic Relaxation Characteristics DOUGLASS S. KALIKA* and SCOTT S. WU Department ...

Research paper thumbnail of Studies on melt spinning. IV. Spinning through a ribbon die

Journal of Applied Polymer Science, 1973

An experimental study has been carried out to investigate effects of stretch ratio on molecular o... more An experimental study has been carried out to investigate effects of stretch ratio on molecular orientation in polypropylene monofilaments which are melt spun from a ribbon die into a water bath with an adjustable air gap distance between the two. By varying the air gap distance and the rate of stretching, a variety of filaments of different, molecular orientations were obtained. Measurements were taken of fiber birefringence of finished filaments under a polarizing microscope with camera attachment and mercury lamp. It has been found, according to the already established relationship between the molecular orientation and birefringence, that the molecular orientation in polypropylene filaments is increased with the rate of stretching. Two other interesting observations were made. One was that the filaments form crimps whose frequency increases with the rate of stretching. The other was that the phenomenon of draw resonance was observed when the rate of stretching was increased beyond a certain critical value.

Research paper thumbnail of Studies on melt spinning. III. Flow instabilities in melt spinning: Melt fracture and draw resonance

Journal of Applied Polymer Science, 1972

An experimental study has been carried out to investigate threadline instabilities in melt spinni... more An experimental study has been carried out to investigate threadline instabilities in melt spinning. Two types of melt threadline instabilities, draw resonance and melt fracture, were observed under both isothermal and nonisothermal spinning conditions. Polymers investigated were polypropylene and polystyrene. Draw resonance was observed as an increase of the takeup speed above a critical value. It was also observed that an increase in take-up speed reduces the severity of melt fracture, whereas once draw resonance OCCUR the amplitude and frequency of the pulsing thread diameter increases with the take-up speed. The phenomenon of draw resonance was investigated by taking motion pictures of the pulsing molten threadliie spun vertically downward. Furthermore, a stability analysis was carried out to explain the experimentally observed draw resonance.

Research paper thumbnail of Studies on melt spinning. II. Analysis of the deformation and heat transfer processes

Journal of Applied Polymer Science, 1972

A generalized, empirical equation is proposed which takes into account the dependence of elongati... more A generalized, empirical equation is proposed which takes into account the dependence of elongational viscosity on both elongation rate and temperature. From this, a mathematical model for simulating the melt spinning process has been developed. The model has been tested against experimentally observed velocity profiles in fibers of polystyrene and high‐density polyethylene spun into an isothermal chamber. It has been found that predicted velocity profiles agree well with experimentally observed ones. The mathematical model has been used to predict velocity and temperature profiles in fibers spun into a cooling medium. The simultaneous solution of momentum and energy balance equations by means of a numerical integration scheme has generated important information such as distributions of force components involved in spinning and distributions of the total rate of heat transfer along the spinning way.

Research paper thumbnail of Uses and processing of cyclic olefin copolymers

Plastics Engineering, 2000

Research paper thumbnail of Cyclic olefin copolymers

Advanced Materials & Processes, 2001

... applications COC may be combined with polyethylene (PE) in monolayer blend films or used in m... more ... applications COC may be combined with polyethylene (PE) in monolayer blend films or used in multilayer films in flexible packaging for food ... When incorporated in the heat-seal layer of bags or stand-up pouches, they can improve hot-tack and ultimate seal strength without ...

Research paper thumbnail of A process for producing microfiber webs containing cycloolefin

The invention relates to a method of producing microfiber nonwovens that contain at least one cyc... more The invention relates to a method of producing microfiber nonwovens that contain at least one cycloolefin polymer by means of a melt-blow method. The invention also relates to articles produced according to this method and to their use.

Research paper thumbnail of Production of poly(arylate) using non-solvent

PURPOSE: To provide a producing method of a polyarylate by which a polyarylate of an improved col... more PURPOSE: To provide a producing method of a polyarylate by which a polyarylate of an improved color is formed, and in which a diluent can be easily separated from the polyarylate and reaction products. CONSTITUTION: A polyarylate is produced by reacting a mixture of a diester of dihydric phenol, at least one kind of aromatic dicarboxylic acid, and an inert diluent comprising a poly(-fluorinated alkylene oxide). COPYRIGHT: (C)1994,JPO

Research paper thumbnail of Preparation of poly(arylate) using a non-solvent

Research paper thumbnail of Preparation of polyarylate of improved color with cobalt salt

Research paper thumbnail of A study of polymer melt flow instabilities in extrusion

Polymer Engineering and Science, 1971

An experimental study is carried out to elucidate the melt fracture mechanism. For the study, the... more An experimental study is carried out to elucidate the melt fracture mechanism. For the study, the electrical outputs of the melt pressure transducers, mounted on the wall of a circular tube, are recorded on a Sanborn recording system. It has been observed from this study that the wall pressures start to fluctuate prior to the inception of visible melt fracture. The frequency and amplitude of the excursion signals are increased as the shear rate is increased up to and beyond the critical value. This behavior has been observed for three polymer samples tested: polystyrene, high density polyethylene, and low density polyethylene. The fluctuations of wall pressures are interpreted as due to an irregular flow of polymer melts at the tube wall. It is further investigated to find the effects of the die entry angle of a capillary, and capillary length-to-diameter ratio on the critical shear rate. A correlation between exit pressure and shear stress has been found for polystyrene and low density polyethylene. It is found that at and above the critical stress, the exit pressure increases abruptly. This is interpreted to be a sudden change in the elastic properties of the materials above melt fracture since Han et a1 have shown that the exit pressure is a measure of the elastic properties.

Research paper thumbnail of Melt flow instabilities in capillary flow of two‐phase polymer systems

Polymer Engineering & Science, 1972

An experimental study was made of melt flow instabilities in extrusion of two‐phase polymer syste... more An experimental study was made of melt flow instabilities in extrusion of two‐phase polymer systems. For the study, blends were prepared from two polymers: polystyrene (Dow Chemical STYRON 686) and high density polyethylene (Union Carbide DMDJ 4309). The experimental technique used in the present study was the same as that described in a previous paper by the authors. The study shows that there are abrupt increases both in exit pressure and in the recoverable shear strain (defined as the ratio of the exit pressure to shear stress) at the critical flow conditions. It has also been found that an addition of a small amount of high density polythylene (2.5 wt‐% and 5.0 wt‐%) increases the critical shear rate of polystyrene and hence results in a higher throughput rate before extrudate distortion is actually observed. This result is explained in terms of the independently determined melt elasticity of the two‐phase systems investigated.

Research paper thumbnail of Studies on Melt Spinning. I. Effect of Molecular Structure and Molecular Weight Distribution on Elongational Viscosity

Transactions of the Society of Rheology, 1972

A melt spinning experiment has been carried out to correlate spinning variables with the molecula... more A melt spinning experiment has been carried out to correlate spinning variables with the molecular weight, molecular weight distribution, and long chain branching of the polymer being spun. Materials chosen for study were three high density polyethylenes having widely different molecular weight distributions, a low density polyethylene having much long chain branching, a polystyrene, and a polypropylene. Molecular characteristics and rheological properties of the materials in simple shearing flow had been independently determined. For the study, a bench scale, melt spinning apparatus was built, and measurements were taken of thread tensions at the take-up device. The axial profiles of thread diameter were measured by a photographic technique. The molten fibers traveled through a heated chamber maintained at the same temperature as the melt. These measurements were then used to determine the elongational viscosity in the absence of any temperature effect.

Research paper thumbnail of Crystallization, melting, and relaxation of modified poly(phenylene sulfide). II. Dynamic relaxation characteristics

Journal of Macromolecular Science, Part B, 1996

Page 1. J. MACROMOL. SC1.-PHYS., B35(2), 179-197 (1996) Crystallization, Melting, and Relaxation ... more Page 1. J. MACROMOL. SC1.-PHYS., B35(2), 179-197 (1996) Crystallization, Melting, and Relaxation of Modified Poly(pheny1ene sulfide). II. Dynamic Relaxation Characteristics DOUGLASS S. KALIKA* and SCOTT S. WU Department ...

Research paper thumbnail of Studies on melt spinning. IV. Spinning through a ribbon die

Journal of Applied Polymer Science, 1973

An experimental study has been carried out to investigate effects of stretch ratio on molecular o... more An experimental study has been carried out to investigate effects of stretch ratio on molecular orientation in polypropylene monofilaments which are melt spun from a ribbon die into a water bath with an adjustable air gap distance between the two. By varying the air gap distance and the rate of stretching, a variety of filaments of different, molecular orientations were obtained. Measurements were taken of fiber birefringence of finished filaments under a polarizing microscope with camera attachment and mercury lamp. It has been found, according to the already established relationship between the molecular orientation and birefringence, that the molecular orientation in polypropylene filaments is increased with the rate of stretching. Two other interesting observations were made. One was that the filaments form crimps whose frequency increases with the rate of stretching. The other was that the phenomenon of draw resonance was observed when the rate of stretching was increased beyond a certain critical value.

Research paper thumbnail of Studies on melt spinning. III. Flow instabilities in melt spinning: Melt fracture and draw resonance

Journal of Applied Polymer Science, 1972

An experimental study has been carried out to investigate threadline instabilities in melt spinni... more An experimental study has been carried out to investigate threadline instabilities in melt spinning. Two types of melt threadline instabilities, draw resonance and melt fracture, were observed under both isothermal and nonisothermal spinning conditions. Polymers investigated were polypropylene and polystyrene. Draw resonance was observed as an increase of the takeup speed above a critical value. It was also observed that an increase in take-up speed reduces the severity of melt fracture, whereas once draw resonance OCCUR the amplitude and frequency of the pulsing thread diameter increases with the take-up speed. The phenomenon of draw resonance was investigated by taking motion pictures of the pulsing molten threadliie spun vertically downward. Furthermore, a stability analysis was carried out to explain the experimentally observed draw resonance.

Research paper thumbnail of Studies on melt spinning. II. Analysis of the deformation and heat transfer processes

Journal of Applied Polymer Science, 1972

A generalized, empirical equation is proposed which takes into account the dependence of elongati... more A generalized, empirical equation is proposed which takes into account the dependence of elongational viscosity on both elongation rate and temperature. From this, a mathematical model for simulating the melt spinning process has been developed. The model has been tested against experimentally observed velocity profiles in fibers of polystyrene and high‐density polyethylene spun into an isothermal chamber. It has been found that predicted velocity profiles agree well with experimentally observed ones. The mathematical model has been used to predict velocity and temperature profiles in fibers spun into a cooling medium. The simultaneous solution of momentum and energy balance equations by means of a numerical integration scheme has generated important information such as distributions of force components involved in spinning and distributions of the total rate of heat transfer along the spinning way.