ASHISH SUKHADIA - Academia.edu (original) (raw)
Papers by ASHISH SUKHADIA
Metallocene Technology in Commercial Applications, 1999
Within the family of PE resins, linear low density PE (LLDPE) resins have found extensive applica... more Within the family of PE resins, linear low density PE (LLDPE) resins have found extensive applications in the areas of food packaging (for example, bakery, candy, frozen foods, ice-bags, etc.), non-food packaging (for example, garment bags, heavy duty sacks, stretch and shrink wrap, etc.) and non-packaging (for example, industrial can liners, agricultural films, medical, trash bags etc.). These numerous applications demand a vast range of application performance benefits that cannot be met by a single resin. A high molecular weight (M w ), broad molecular weight distribution (MWD) and often very low levels of long chain branching (LCB) typify chromium catalyst PE resins. Ziegler–Natta (Z–N) resins are typically narrower in MWD than chromium resins and contain no LCB. Metallocene resins are typically even narrower in MWD than Z–N resins and may or may not contain any LCB depending on the catalyst and process employed. Thus, it is clear that these three catalysts viz. chromium, Z–N and metallocene can yield PE resins with widely different molecular and rheological properties. This chapter examines the blown film processing–structure–property behavior and trade-offs with three different LLDPE resins from each catalyst mentioned.
Journal of Plastic Film & Sheeting, 1994
Blown film processing is an important but very complex process. A blown film scale-up strategy pr... more Blown film processing is an important but very complex process. A blown film scale-up strategy proposed earlier by T. Kanai et al. was revisited in this work. The blown film process was scaled up very successfully using that strategy. Furthermore, the strategy is shown by this work to be independent of resin or polymer type, die size, die gap and extrusion differences such as die and extruder shear rates provided that all of the other criteria set by the strategy are fulfilled. Using bubble kinematics it was found that the principal strain rate profiles in the machine and transverse directions and the cooling rate pro files were largely similar under the scale-up conditions. High resolution scan ning electron micrographs showed that the stacked lamellar morphology that is developed under scale-up conditions is also largely similar-resulting in equivalent film properties. Lastly, some trends between the strain rates, mor phology and film properties are suggested.
Metallocene Catalyzed Polymers, 1998
Metallocene catalyst polyolefins are widely regarded as a new generation of resins entering the m... more Metallocene catalyst polyolefins are widely regarded as a new generation of resins entering the marketplace. A number of metallocene catalyzed linear low density polyethylene (m-LLDPE) resins, ranging in density from 0.905-0.942 g/cc and in melt index (MI) from 0.7-3 MI, were made using the Phillips slurry loop process; these resins referred to as PPCo-M, were evaluated for blown film applications. The effects of density, molecular weight, processing aid, slip/antiblock agents and film thickness on the processability, film property performance (impact and tear strengths) and clarity of blown films were examined in detail in this work. Metallocene resins produced in the Phillips slurry loop process offer a very good balance of processability and performance characteristics, which can be further optimized for various applications by appropriate choice of resin and processing conditions.
Journal of Plastic Film and Sheeting, 2000
ABSTRACT In this paper, the processing-structure-property (P-S-P) behavior and trade-offs observe... more ABSTRACT In this paper, the processing-structure-property (P-S-P) behavior and trade-offs observed with three LLDPE resins made from chromium, metallocene and Ziegler-Natta catalysts were examined and critically compared. The basic molecular and rheological properties were examined. The blown film performance of these resins was examined with respect to the effects of film thickness and molecular orientation on film properties. Also, the processability of these resins was compared through an examination of the typical extrusion and film blowing processing parameters. Finally, an attempt was made to highlight the advantages and disadvantages of each resin type as they apply to blown film applications. The results demonstrate the LLDPE resins from these various catalysts are dramatically different in nature, thereby resulting in different trade-offs with respect to their P-S-P behavior in film blowing.
Un proceso para producir una composicion polimerica, comprendiendo dicho proceso la incorporacion... more Un proceso para producir una composicion polimerica, comprendiendo dicho proceso la incorporacion de un polimero de base con distribucion estrecha por peso molecular y un componente polimerico de alto peso molecular para producir dicha composicion polimerica; en donde dicho polimero de base es un polimero de etileno que tiene un Mw/Mn menor de 5 y un indice del flujo de fusion desde 0, 2 g/10 min hasta 20 g/10 min; y en donde dicho componente polimerico de alto peso molecular tiene una distribucion por peso molecular tal que al menos una parte sustancial de sus moleculas tiene un peso molecular de mas de un millon, siendo incorporado dicho componente polimerico de alto peso molecular en una cantidad para dar 0, 1 a 10 % en peso, en base al peso total de dicha composicion polimerica, de dichas moleculas que tienen un peso molecular mayor que un millon.
Cette invention concerne des polymeres a base d'ethylene obtenus a l'aide de doubles syst... more Cette invention concerne des polymeres a base d'ethylene obtenus a l'aide de doubles systemes de catalyseurs de type metallocene. Ces polymeres ont de basses densites, des poids moleculaires eleves, et de larges distributions des poids moleculaires, la majorite des ramifications a chaine longue se trouvant dans le composant de poids moleculaire inferieur du polymere, et la majorite des ramifications a chaine courte se trouvant dans le composant de poids moleculaire plus eleve du polymere. Les films produits a partir de ces polymeres ont une resistance au choc et aux perforations amelioree.
A catalyst composition comprising a first metallocene compound, a second metallocene compound, at... more A catalyst composition comprising a first metallocene compound, a second metallocene compound, at least one chemically treated calcined solid oxide, and at least one organoaluminum compound, wherein: a) the first metallocene compound has the following formula: (X1) (X2) (X3) (X4) Zr; wherein (X1) and (X2) are independently a monosubstituted cyclopentadienyl, a monosubstituted indenyl, a monosubstituted fluorenyl, or a partially saturated, monosubstituted analog thereof; wherein each substituent in (X1) and (X2) is independently a linear or branched aliphatic group, wherein the aliphatic group is unsubstituted or substituted, any of which has 1 to 20 carbon atoms; wherein (X3), (X4), and any substituent in the aliphatic group substituted in (X1) and (X2) are independently an aliphatic group, an aromatic group, a cyclic group, a combination of aliphatic and cyclic groups, a group with oxygen, a group with sulfur, a group with nitrogen, a group with phosphorus, a group with arsenic, a ...
A process for producing a polymer composition, said process comprising incorporating a narrow bas... more A process for producing a polymer composition, said process comprising incorporating a narrow base polymer molecular weight distribution and a polymeric high molecular weight component to produce said polymer composition; wherein said base polymer is an ethylene polymer having a Mw / Mn less than 5 and an index of melt flow from 0, 2 g / 10 min to 20 g / 10 min; and wherein said polymer component of high molecular weight has a molecular weight distribution such that at least a substantial portion of its molecules have a molecular weight of over one million, being incorporated said polymeric component high molecular weight in an amount to give 0, 1 to 10% by weight, based on the total weight of said polymer composition, of said molecules having a molecular weight greater than one million.
An ethylene polymer, characterized by a melt index of 7 to 15 g / 10 min wherein the melt index i... more An ethylene polymer, characterized by a melt index of 7 to 15 g / 10 min wherein the melt index is measured according to ASTM D-1238, Condition E (190 ° C, 2.16 kg); a density of 0.916 to 0.930 g / cm3, wherein the density is measured in accordance with ASTM D-1505; an activation energy Ea flow 38 to 42 kJ / mol in which the flow activation energy is determined by performing a time-temperature superposition of dynamic frequency data obtained at 150 ° C, 190 ° C and 230 ° C; a polydispersion index (Mw / Mn) of 5 to 10; an Mz 500 to 1,100 kg / mol; a molecular weight Mw of 80 to 130 kg / mol; and the number of Long Chain Branches per 1,000 carbon atoms (LCB / 1000 carbon atoms) is from 0.02 to 0.18 in the molecular weight range Mw of 100 to 1,000 kg / mol, in which polydispersity index, Mw, Mn and Mz are determined from SEC-MALS of LCB and is determined using the Zimm-Stockmayer approach.
La presente invention a trait a des compositions de catalyseur comportant un premier compose meta... more La presente invention a trait a des compositions de catalyseur comportant un premier compose metallocene, un deuxieme compose metallocene, au moins un oxyde solide soumis a un traitement chimique, et au moins un compose organoaluminium. La presente invention a egalement trait a des procedes de preparation et d'utilisation de compositions de catalyseurs et de nouvelles polyolefines. Les compositions et procedes de l'invention permettent d'obtenir des polymeres et des copolymeres d'ethylene a indice de fluidite inferieure, a tenue a la fusion accrue, et de bonnes proprietes de resistance dans le sens machine.
La presente invention concerne des polymeres a base d'ethylene presentant une faible densite ... more La presente invention concerne des polymeres a base d'ethylene presentant une faible densite et une distribution etroite des masses moleculaires, mais une grande resistance a la fusion, et utilisables dans le cadre du traitement de feuilles soufflees. Lesdits polymeres peuvent etre produits par traitement au peroxyde d'une resine catalysee par un metallocene.
Plastics Engineering, 2016
Plastics Engineering, 2013
he well-established long-term safe performance of polyethylene (PE) pipe over its service history... more he well-established long-term safe performance of polyethylene (PE) pipe over its service history has made it the material of choice for lower pressure gas distribution pipelines. Because of availability, low cost, ease of installation, and low maintenance, medium density polyethylene (MDPE) has been a customary material of choice for gas distribution lines for several decades. An important design criterion for use of MDPE pipe in gas distribution systems is the pipeʼs resistance to rapid crack propagation (RCP), a specific mode of pipeline failure whereby under specific conditions of pressure, temperature, pipe size, and loading, and in the presence of an initiating event, a rapidly growing longitudinal crack develops that may propagate a significant distance before crack arrest. Although RCP occurrences in PE pipelines are rare, it is important to understand the RCP phenomenon, so that PE pipes continue to be designed to prevent RCP events. The standard methods available for determining the RCP resistance of PE pipe are the ISO 13478 Full Scale (FS) test 1 and ISO 13477 Small Scale Steady State (S4) test 2. While these two test methods are in agreement with respect to purpose (i.e., characterization of RCP performance), they differ in execution and in the results that are produced. The FS test is the
Metallocene Technology in Commercial Applications, 1999
Within the family of PE resins, linear low density PE (LLDPE) resins have found extensive applica... more Within the family of PE resins, linear low density PE (LLDPE) resins have found extensive applications in the areas of food packaging (for example, bakery, candy, frozen foods, ice-bags, etc.), non-food packaging (for example, garment bags, heavy duty sacks, stretch and shrink wrap, etc.) and non-packaging (for example, industrial can liners, agricultural films, medical, trash bags etc.). These numerous applications demand a vast range of application performance benefits that cannot be met by a single resin. A high molecular weight (M w ), broad molecular weight distribution (MWD) and often very low levels of long chain branching (LCB) typify chromium catalyst PE resins. Ziegler–Natta (Z–N) resins are typically narrower in MWD than chromium resins and contain no LCB. Metallocene resins are typically even narrower in MWD than Z–N resins and may or may not contain any LCB depending on the catalyst and process employed. Thus, it is clear that these three catalysts viz. chromium, Z–N and metallocene can yield PE resins with widely different molecular and rheological properties. This chapter examines the blown film processing–structure–property behavior and trade-offs with three different LLDPE resins from each catalyst mentioned.
Journal of Plastic Film & Sheeting, 1994
Blown film processing is an important but very complex process. A blown film scale-up strategy pr... more Blown film processing is an important but very complex process. A blown film scale-up strategy proposed earlier by T. Kanai et al. was revisited in this work. The blown film process was scaled up very successfully using that strategy. Furthermore, the strategy is shown by this work to be independent of resin or polymer type, die size, die gap and extrusion differences such as die and extruder shear rates provided that all of the other criteria set by the strategy are fulfilled. Using bubble kinematics it was found that the principal strain rate profiles in the machine and transverse directions and the cooling rate pro files were largely similar under the scale-up conditions. High resolution scan ning electron micrographs showed that the stacked lamellar morphology that is developed under scale-up conditions is also largely similar-resulting in equivalent film properties. Lastly, some trends between the strain rates, mor phology and film properties are suggested.
Metallocene Catalyzed Polymers, 1998
Metallocene catalyst polyolefins are widely regarded as a new generation of resins entering the m... more Metallocene catalyst polyolefins are widely regarded as a new generation of resins entering the marketplace. A number of metallocene catalyzed linear low density polyethylene (m-LLDPE) resins, ranging in density from 0.905-0.942 g/cc and in melt index (MI) from 0.7-3 MI, were made using the Phillips slurry loop process; these resins referred to as PPCo-M, were evaluated for blown film applications. The effects of density, molecular weight, processing aid, slip/antiblock agents and film thickness on the processability, film property performance (impact and tear strengths) and clarity of blown films were examined in detail in this work. Metallocene resins produced in the Phillips slurry loop process offer a very good balance of processability and performance characteristics, which can be further optimized for various applications by appropriate choice of resin and processing conditions.
Journal of Plastic Film and Sheeting, 2000
ABSTRACT In this paper, the processing-structure-property (P-S-P) behavior and trade-offs observe... more ABSTRACT In this paper, the processing-structure-property (P-S-P) behavior and trade-offs observed with three LLDPE resins made from chromium, metallocene and Ziegler-Natta catalysts were examined and critically compared. The basic molecular and rheological properties were examined. The blown film performance of these resins was examined with respect to the effects of film thickness and molecular orientation on film properties. Also, the processability of these resins was compared through an examination of the typical extrusion and film blowing processing parameters. Finally, an attempt was made to highlight the advantages and disadvantages of each resin type as they apply to blown film applications. The results demonstrate the LLDPE resins from these various catalysts are dramatically different in nature, thereby resulting in different trade-offs with respect to their P-S-P behavior in film blowing.
Un proceso para producir una composicion polimerica, comprendiendo dicho proceso la incorporacion... more Un proceso para producir una composicion polimerica, comprendiendo dicho proceso la incorporacion de un polimero de base con distribucion estrecha por peso molecular y un componente polimerico de alto peso molecular para producir dicha composicion polimerica; en donde dicho polimero de base es un polimero de etileno que tiene un Mw/Mn menor de 5 y un indice del flujo de fusion desde 0, 2 g/10 min hasta 20 g/10 min; y en donde dicho componente polimerico de alto peso molecular tiene una distribucion por peso molecular tal que al menos una parte sustancial de sus moleculas tiene un peso molecular de mas de un millon, siendo incorporado dicho componente polimerico de alto peso molecular en una cantidad para dar 0, 1 a 10 % en peso, en base al peso total de dicha composicion polimerica, de dichas moleculas que tienen un peso molecular mayor que un millon.
Cette invention concerne des polymeres a base d'ethylene obtenus a l'aide de doubles syst... more Cette invention concerne des polymeres a base d'ethylene obtenus a l'aide de doubles systemes de catalyseurs de type metallocene. Ces polymeres ont de basses densites, des poids moleculaires eleves, et de larges distributions des poids moleculaires, la majorite des ramifications a chaine longue se trouvant dans le composant de poids moleculaire inferieur du polymere, et la majorite des ramifications a chaine courte se trouvant dans le composant de poids moleculaire plus eleve du polymere. Les films produits a partir de ces polymeres ont une resistance au choc et aux perforations amelioree.
A catalyst composition comprising a first metallocene compound, a second metallocene compound, at... more A catalyst composition comprising a first metallocene compound, a second metallocene compound, at least one chemically treated calcined solid oxide, and at least one organoaluminum compound, wherein: a) the first metallocene compound has the following formula: (X1) (X2) (X3) (X4) Zr; wherein (X1) and (X2) are independently a monosubstituted cyclopentadienyl, a monosubstituted indenyl, a monosubstituted fluorenyl, or a partially saturated, monosubstituted analog thereof; wherein each substituent in (X1) and (X2) is independently a linear or branched aliphatic group, wherein the aliphatic group is unsubstituted or substituted, any of which has 1 to 20 carbon atoms; wherein (X3), (X4), and any substituent in the aliphatic group substituted in (X1) and (X2) are independently an aliphatic group, an aromatic group, a cyclic group, a combination of aliphatic and cyclic groups, a group with oxygen, a group with sulfur, a group with nitrogen, a group with phosphorus, a group with arsenic, a ...
A process for producing a polymer composition, said process comprising incorporating a narrow bas... more A process for producing a polymer composition, said process comprising incorporating a narrow base polymer molecular weight distribution and a polymeric high molecular weight component to produce said polymer composition; wherein said base polymer is an ethylene polymer having a Mw / Mn less than 5 and an index of melt flow from 0, 2 g / 10 min to 20 g / 10 min; and wherein said polymer component of high molecular weight has a molecular weight distribution such that at least a substantial portion of its molecules have a molecular weight of over one million, being incorporated said polymeric component high molecular weight in an amount to give 0, 1 to 10% by weight, based on the total weight of said polymer composition, of said molecules having a molecular weight greater than one million.
An ethylene polymer, characterized by a melt index of 7 to 15 g / 10 min wherein the melt index i... more An ethylene polymer, characterized by a melt index of 7 to 15 g / 10 min wherein the melt index is measured according to ASTM D-1238, Condition E (190 ° C, 2.16 kg); a density of 0.916 to 0.930 g / cm3, wherein the density is measured in accordance with ASTM D-1505; an activation energy Ea flow 38 to 42 kJ / mol in which the flow activation energy is determined by performing a time-temperature superposition of dynamic frequency data obtained at 150 ° C, 190 ° C and 230 ° C; a polydispersion index (Mw / Mn) of 5 to 10; an Mz 500 to 1,100 kg / mol; a molecular weight Mw of 80 to 130 kg / mol; and the number of Long Chain Branches per 1,000 carbon atoms (LCB / 1000 carbon atoms) is from 0.02 to 0.18 in the molecular weight range Mw of 100 to 1,000 kg / mol, in which polydispersity index, Mw, Mn and Mz are determined from SEC-MALS of LCB and is determined using the Zimm-Stockmayer approach.
La presente invention a trait a des compositions de catalyseur comportant un premier compose meta... more La presente invention a trait a des compositions de catalyseur comportant un premier compose metallocene, un deuxieme compose metallocene, au moins un oxyde solide soumis a un traitement chimique, et au moins un compose organoaluminium. La presente invention a egalement trait a des procedes de preparation et d'utilisation de compositions de catalyseurs et de nouvelles polyolefines. Les compositions et procedes de l'invention permettent d'obtenir des polymeres et des copolymeres d'ethylene a indice de fluidite inferieure, a tenue a la fusion accrue, et de bonnes proprietes de resistance dans le sens machine.
La presente invention concerne des polymeres a base d'ethylene presentant une faible densite ... more La presente invention concerne des polymeres a base d'ethylene presentant une faible densite et une distribution etroite des masses moleculaires, mais une grande resistance a la fusion, et utilisables dans le cadre du traitement de feuilles soufflees. Lesdits polymeres peuvent etre produits par traitement au peroxyde d'une resine catalysee par un metallocene.
Plastics Engineering, 2016
Plastics Engineering, 2013
he well-established long-term safe performance of polyethylene (PE) pipe over its service history... more he well-established long-term safe performance of polyethylene (PE) pipe over its service history has made it the material of choice for lower pressure gas distribution pipelines. Because of availability, low cost, ease of installation, and low maintenance, medium density polyethylene (MDPE) has been a customary material of choice for gas distribution lines for several decades. An important design criterion for use of MDPE pipe in gas distribution systems is the pipeʼs resistance to rapid crack propagation (RCP), a specific mode of pipeline failure whereby under specific conditions of pressure, temperature, pipe size, and loading, and in the presence of an initiating event, a rapidly growing longitudinal crack develops that may propagate a significant distance before crack arrest. Although RCP occurrences in PE pipelines are rare, it is important to understand the RCP phenomenon, so that PE pipes continue to be designed to prevent RCP events. The standard methods available for determining the RCP resistance of PE pipe are the ISO 13478 Full Scale (FS) test 1 and ISO 13477 Small Scale Steady State (S4) test 2. While these two test methods are in agreement with respect to purpose (i.e., characterization of RCP performance), they differ in execution and in the results that are produced. The FS test is the