Pub Date : 2022-04-08DOI: 10.1177/87560879221089432
Full circle: ZnII-complexes bearing half-salan ligands facilitate the mild and selective degradation of various commercial polyesters and polycarbonates into value-added products (green solvents and chemical building blocks). We report the first example of discrete metal-mediated poly (bisphenol A carbonate) methanolysis being appreciably active at room temperature, whilst the production of several renewable poly (ester-amides)s demonstrates a completely circular PET waste upcycling approach. ZnII-complexes bearing half-salan ligands were exploited in the mild and selective chemical upcycling of various commercial polyesters and polycarbonates. Remarkably, we report the first example of discrete metal-mediated poly (bisphenol A carbonate) (BPA-PC) methanolysis being appreciably active at room temperature. Indeed, Zn (2)2 and Zn (2)Et achieved complete BPA-PC consumption within 12–18 min in 2-Me-THF, noting high bisphenol A (BPA) yields (SBPA = 85–91%) within 2–4 h. Further kinetic analysis found such catalysts to possess kapp values of 0.28 ± 0.040 and 0.47 ± 0.049 min−1, respectively, at 4 wt%, the highest reported to date. A completely circular upcycling approach to plastic waste was demonstrated through the production of several renewable poly (ester-amide)s (PEAs), based on a terephthalamide monomer derived from bottle-grade poly (ethylene terephthalate) (PET), which exhibited excellent thermal properties.
完整循环:含半萨兰配体的ni -配合物促进了各种商业聚酯和聚碳酸酯的温和和选择性降解,成为增值产品(绿色溶剂和化学构建模块)。我们报告了离散金属介导的聚(双酚A碳酸酯)甲醇分解在室温下具有明显活性的第一个例子,同时几种可再生聚(酯酰胺)的生产展示了一个完全循环的PET废物升级回收方法。含半萨兰配体的ni -配合物被用于各种商用聚酯和聚碳酸酯的温和和选择性化学升级。值得注意的是,我们报告了离散金属介导的聚双酚A碳酸酯(BPA-PC)甲醇分解在室温下明显活跃的第一个例子。事实上,Zn(2)2和Zn (2)Et在2- me - thf中在12-18分钟内完全消耗了BPA- pc,并在2- 4小时内产生了高双酚A (BPA)收率(SBPA = 85-91%)。进一步的动力学分析发现,这些催化剂在4 wt%时分别具有0.28±0.040和0.47±0.049 min - 1的kapp值,这是迄今为止报道的最高值。通过从瓶级聚对苯二甲酸乙酯(PET)中提取的对苯二甲酸乙酯(PET)单体生产几种可再生聚(酯酰胺)(豌豆),展示了一种完全循环的塑料废物升级回收方法,这种聚合物具有优异的热性能。
{"title":"Industry News","authors":"","doi":"10.1177/87560879221089432","DOIUrl":"https://doi.org/10.1177/87560879221089432","url":null,"abstract":"<p>Full circle: ZnII-complexes bearing half-salan ligands facilitate the mild and selective degradation of various commercial polyesters and polycarbonates into value-added products (green solvents and chemical building blocks). We report the first example of discrete metal-mediated poly (bisphenol A carbonate) methanolysis being appreciably active at room temperature, whilst the production of several renewable poly (ester-amides)s demonstrates a completely circular PET waste upcycling approach. ZnII-complexes bearing half-salan ligands were exploited in the mild and selective chemical upcycling of various commercial polyesters and polycarbonates. Remarkably, we report the first example of discrete metal-mediated poly (bisphenol A carbonate) (BPA-PC) methanolysis being appreciably active at room temperature. Indeed, Zn (2)2 and Zn (2)Et achieved complete BPA-PC consumption within 12–18 min in 2-Me-THF, noting high bisphenol A (BPA) yields (SBPA = 85–91%) within 2–4 h. Further kinetic analysis found such catalysts to possess kapp values of 0.28 ± 0.040 and 0.47 ± 0.049 min−1, respectively, at 4 wt%, the highest reported to date. A completely circular upcycling approach to plastic waste was demonstrated through the production of several renewable poly (ester-amide)s (PEAs), based on a terephthalamide monomer derived from bottle-grade poly (ethylene terephthalate) (PET), which exhibited excellent thermal properties.</p>","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"36 2","pages":""},"PeriodicalIF":3.1,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138524598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-25DOI: 10.1177/87560879221089431
John R. WagnerJr
The sixth wave of this COVID-19 corona virus pandemic is winding down. Governments and regulatory agencies are rescinding mask mandates in light of public opposition and the desire to get back to normal, whatever that is. At this writing, we are at 440 million cases worldwide and rising by ∼ 1.5 – 2 million cases per day worldwide and there have been > 6 million deaths which are increasing by ∼ 10,000 per day. Some areas are doing better than others; however, the case rate and the death rate per day is at or above the maximum for the fi rst wave. Areas that have high vaccination rates and good healthcare systems are learning to cope with this disease. I am concerned with what will happen when caution is relaxed and for the safety in areas where vaccination rates are low or have health systems that are challenged by this virus.
{"title":"From the editor","authors":"John R. WagnerJr","doi":"10.1177/87560879221089431","DOIUrl":"https://doi.org/10.1177/87560879221089431","url":null,"abstract":"The sixth wave of this COVID-19 corona virus pandemic is winding down. Governments and regulatory agencies are rescinding mask mandates in light of public opposition and the desire to get back to normal, whatever that is. At this writing, we are at 440 million cases worldwide and rising by ∼ 1.5 – 2 million cases per day worldwide and there have been > 6 million deaths which are increasing by ∼ 10,000 per day. Some areas are doing better than others; however, the case rate and the death rate per day is at or above the maximum for the fi rst wave. Areas that have high vaccination rates and good healthcare systems are learning to cope with this disease. I am concerned with what will happen when caution is relaxed and for the safety in areas where vaccination rates are low or have health systems that are challenged by this virus.","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"1 1","pages":"175 - 176"},"PeriodicalIF":3.1,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90726079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-25DOI: 10.1177/87560879211058679
Kornchanok Akaradechakul, Peerapong Chanthot, N. Kerddonfag, C. Pattamaprom
This is the first study investigating how polycarbodiimide (PCDI) delays thermal degradation of poly(lactic acid)/natural rubber blends (PLA/NR) during the preparation of PLA/NR masterbatches (MB) and PLA/MB compounds for the film blowing process. The PCDI concentration used in this work was from 0 to 1 wt%. The torque plastograms, FTIR, and 1H-NMR spectra indicated the successful chain extending reaction between the PCDI carbodiimide group and the PLA carboxyl group, and there was no reaction with NR domains. The reaction increased the PLA/MB compounds’ viscosity and improved processability and mechanical properties of PLA/MB blown films. The optimal PCDI content for the highest melt strength, film blowing stability, and mechanical properties was at 0.25 wt% PCDI. Undesirable gel spots were observed in the PLA/MB blown film at PCDI concentrations higher than 0.5 wt%.
{"title":"The effect of polycarbodiimide chain extender on thermal stability and mechanical properties of biobased poly(lactic acid)/natural rubber blown films","authors":"Kornchanok Akaradechakul, Peerapong Chanthot, N. Kerddonfag, C. Pattamaprom","doi":"10.1177/87560879211058679","DOIUrl":"https://doi.org/10.1177/87560879211058679","url":null,"abstract":"This is the first study investigating how polycarbodiimide (PCDI) delays thermal degradation of poly(lactic acid)/natural rubber blends (PLA/NR) during the preparation of PLA/NR masterbatches (MB) and PLA/MB compounds for the film blowing process. The PCDI concentration used in this work was from 0 to 1 wt%. The torque plastograms, FTIR, and 1H-NMR spectra indicated the successful chain extending reaction between the PCDI carbodiimide group and the PLA carboxyl group, and there was no reaction with NR domains. The reaction increased the PLA/MB compounds’ viscosity and improved processability and mechanical properties of PLA/MB blown films. The optimal PCDI content for the highest melt strength, film blowing stability, and mechanical properties was at 0.25 wt% PCDI. Undesirable gel spots were observed in the PLA/MB blown film at PCDI concentrations higher than 0.5 wt%.","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"42 1","pages":"396 - 415"},"PeriodicalIF":3.1,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90809796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.1177/87560879221089430
Shari Kraber
Aliasing in a fractional-factorial design means that it is not possible to estimate all effects because the experimental matrix has fewer unique combinations than a full-factorial design. The alias structure defines how effects are combined. When the researcher understands the basics of aliasing, they can better select a design that meets their experimental objectives. Starting with a layman’s definition of an alias, it is two or more names for one thing. Referring to a person, it could be “Fred, also known as (aliased) George.” There is only one person, but they go by two names. As will be shown shortly, in a fractional-factorial design, there will be one calculated effect estimate that is assigned multiple names (aliases). This example (Figure 1) is a 2̂ 3, 8-run factorial design. These eight runs can be used to estimate all possible factor effects including the main effects A, B, and C, followed by the interaction effects AB, AB, BC and ABC. An additional column “I” is the Identity column, representing the intercept for the polynomial. Each column in the full-factorial design is a unique set of pluses and minuses, resulting in independent estimates of the factor effects. An effect is calculated by averaging the response values where the factor is set high (+) and subtracting the average response from the rows where the term is set low ( ). Mathematically, this is written as follows: In this example, the A effect is calculated like this: The last row in Figure 1 shows the calculation result for the other main effects, 2-factor and 3-factor interactions and the Identity column. In a half-fraction design (Figure 2), only half of the runs are completed. According to standard practice, we eliminate all the runs where the ABC column has a negative sign. Now the columns are not unique—pairs of columns have the identical pattern of pluses and minuses. The effect estimates are confounded (aliased) because they are changing in exactly the same pattern. The A column is the same pattern as the BC column (A = BC).
{"title":"Statistician’s corner what’s behind aliasing in fractional-factorial designs","authors":"Shari Kraber","doi":"10.1177/87560879221089430","DOIUrl":"https://doi.org/10.1177/87560879221089430","url":null,"abstract":"Aliasing in a fractional-factorial design means that it is not possible to estimate all effects because the experimental matrix has fewer unique combinations than a full-factorial design. The alias structure defines how effects are combined. When the researcher understands the basics of aliasing, they can better select a design that meets their experimental objectives. Starting with a layman’s definition of an alias, it is two or more names for one thing. Referring to a person, it could be “Fred, also known as (aliased) George.” There is only one person, but they go by two names. As will be shown shortly, in a fractional-factorial design, there will be one calculated effect estimate that is assigned multiple names (aliases). This example (Figure 1) is a 2̂ 3, 8-run factorial design. These eight runs can be used to estimate all possible factor effects including the main effects A, B, and C, followed by the interaction effects AB, AB, BC and ABC. An additional column “I” is the Identity column, representing the intercept for the polynomial. Each column in the full-factorial design is a unique set of pluses and minuses, resulting in independent estimates of the factor effects. An effect is calculated by averaging the response values where the factor is set high (+) and subtracting the average response from the rows where the term is set low ( ). Mathematically, this is written as follows: In this example, the A effect is calculated like this: The last row in Figure 1 shows the calculation result for the other main effects, 2-factor and 3-factor interactions and the Identity column. In a half-fraction design (Figure 2), only half of the runs are completed. According to standard practice, we eliminate all the runs where the ABC column has a negative sign. Now the columns are not unique—pairs of columns have the identical pattern of pluses and minuses. The effect estimates are confounded (aliased) because they are changing in exactly the same pattern. The A column is the same pattern as the BC column (A = BC).","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"8 1","pages":"187 - 190"},"PeriodicalIF":3.1,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78855322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-18DOI: 10.1177/87560879211063475
M. Paul, B. Morris, J. Weinhold, K. Hausmann
Multilayer films are widely used in flexible packaging to provide an optimum balance of performance and cost. Orientation in the semi-solid state via tenter frame, double bubble, and machine direction orientation processes enhances barrier and mechanical properties and offers a means toward light weighting packaging structures. Interlayer adhesion of coextruded films, however, substantially decreases during the orientation as the generated new interfacial area decreases bond density and chain segments are stressed. A guideline is proposed that provides insight into how changes during orientation in chain segment penetration, entanglement, bond orientation, and density affect peel strength because of semi-solid state orientation. Examples are provided that use these insights to design novel tie resins with improved performance.
{"title":"The effect of stretching and tie layer composition on adhesion strength of multi-layered films","authors":"M. Paul, B. Morris, J. Weinhold, K. Hausmann","doi":"10.1177/87560879211063475","DOIUrl":"https://doi.org/10.1177/87560879211063475","url":null,"abstract":"Multilayer films are widely used in flexible packaging to provide an optimum balance of performance and cost. Orientation in the semi-solid state via tenter frame, double bubble, and machine direction orientation processes enhances barrier and mechanical properties and offers a means toward light weighting packaging structures. Interlayer adhesion of coextruded films, however, substantially decreases during the orientation as the generated new interfacial area decreases bond density and chain segments are stressed. A guideline is proposed that provides insight into how changes during orientation in chain segment penetration, entanglement, bond orientation, and density affect peel strength because of semi-solid state orientation. Examples are provided that use these insights to design novel tie resins with improved performance.","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"105 1","pages":"351 - 368"},"PeriodicalIF":3.1,"publicationDate":"2022-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80643932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-18DOI: 10.1177/87560879211059859
Ayesha Kausar
Polyurethane and polystyrene are significant thermoplastic polymers having unique physical properties. This article considers the research trials on the fabrication, remarkable features, and technical applications of the polyurethane/polystyrene nanocomposites. The carbonaceous nano particles and inorganic nanofillers used with the polyurethane/polystyrene blend or copolymer are carbon nanotube, graphene, nanoclay, silica nanoparticles, and others. The considerable improvements in the physical properties of the polyurethane/polystyrene blend may occur through the nanofiller addition. The physical or covalent interactions between the blend or copolymer components and nanofillers may also positively affect the nanocomposite properties. The fabrication strategies used for the polyurethane/polystyrene nanocomposites include solution method, in situ method, melt blending, and several nanocomposite processing approaches. The structure, morphology, electrical conductivity, thermal stability, mechanical strength, and several other physical properties of the high performance polyurethane/polystyrene nanocomposites have been explored. Major application areas identified are shape memory, membrane, and gas transport properties.
{"title":"Effect of nanofillers on polyurethane/polystyrene matrix nanocomposites: Characteristics and forthcoming developments","authors":"Ayesha Kausar","doi":"10.1177/87560879211059859","DOIUrl":"https://doi.org/10.1177/87560879211059859","url":null,"abstract":"Polyurethane and polystyrene are significant thermoplastic polymers having unique physical properties. This article considers the research trials on the fabrication, remarkable features, and technical applications of the polyurethane/polystyrene nanocomposites. The carbonaceous nano particles and inorganic nanofillers used with the polyurethane/polystyrene blend or copolymer are carbon nanotube, graphene, nanoclay, silica nanoparticles, and others. The considerable improvements in the physical properties of the polyurethane/polystyrene blend may occur through the nanofiller addition. The physical or covalent interactions between the blend or copolymer components and nanofillers may also positively affect the nanocomposite properties. The fabrication strategies used for the polyurethane/polystyrene nanocomposites include solution method, in situ method, melt blending, and several nanocomposite processing approaches. The structure, morphology, electrical conductivity, thermal stability, mechanical strength, and several other physical properties of the high performance polyurethane/polystyrene nanocomposites have been explored. Major application areas identified are shape memory, membrane, and gas transport properties.","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"4 1","pages":"438 - 457"},"PeriodicalIF":3.1,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81614673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-06DOI: 10.1177/87560879211046188
Katsunori Ishida, Shotaro Nishitsuji, Ken Miyata
This study focuses on controlling the interfacial adhesive strength between heat-sealed styrene-co-butadiene block copolymer (SBC) and glycol-modified polyethylene terephthalate (PETG) multilayer films. In comparison, the interfacial bond strength of coextruded PETG/SBC/PETG films was weaker. The lamella structures of SBC and free polybutadiene increased the interfacial adhesive strength. The coextruded films with applied thermal pressing were also examined. When exposed to heat, the interfacial adhesive strength improved. The butadiene layer segregated along the adhesive interface, as observed by transmission electron microscopy. The butadiene layer improved the interfacial adhesive strength. The applied pressure caused the butadiene layer to segregate in a parallel manner along the adhesive interface. The developed lamellar structure did not increase adhesive strength. We considered that the adhesive strength decreased due to a thinner butadiene layer with higher pressure. We concluded that adhesive segregation along the adhesive interface improved the bond strength.
{"title":"Effect of temperature and pressure on the interfacial morphology and bond strength of thermally laminated glycol-modified polyethylene terephthalate/styrene-co-butadiene block copolymer films and comparison with coextruded (polyethylene terephthalate/styrene-co-butadiene block copolymer/polyethylene terephthalate) and polyethylene terephthalate/styrene-co-butadiene block copolymer/polyethylene terephthalate films heated with applied pressure after extrusion","authors":"Katsunori Ishida, Shotaro Nishitsuji, Ken Miyata","doi":"10.1177/87560879211046188","DOIUrl":"https://doi.org/10.1177/87560879211046188","url":null,"abstract":"<p>This study focuses on controlling the interfacial adhesive strength between heat-sealed styrene-co-butadiene block copolymer (SBC) and glycol-modified polyethylene terephthalate (PETG) multilayer films. In comparison, the interfacial bond strength of coextruded PETG/SBC/PETG films was weaker. The lamella structures of SBC and free polybutadiene increased the interfacial adhesive strength. The coextruded films with applied thermal pressing were also examined. When exposed to heat, the interfacial adhesive strength improved. The butadiene layer segregated along the adhesive interface, as observed by transmission electron microscopy. The butadiene layer improved the interfacial adhesive strength. The applied pressure caused the butadiene layer to segregate in a parallel manner along the adhesive interface. The developed lamellar structure did not increase adhesive strength. We considered that the adhesive strength decreased due to a thinner butadiene layer with higher pressure. We concluded that adhesive segregation along the adhesive interface improved the bond strength.</p>","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"13 2","pages":""},"PeriodicalIF":3.1,"publicationDate":"2022-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138524599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-31DOI: 10.1177/87560879211058768
Fanny Traon, Y. Grohens, Y. Corre
For amorphous polymers, restoring forces are generated by the progressive orientation of the macromolecular chains in the stretching direction leading to a decrease in the system entropy. Orienting the chains in the future stretching direction thus reduces the entropy variation induced by the stretching and limits the entropic restoring force magnitude. Entropic restoring forces created during stretching have been correlated to the number of junction points by previous studies. Reducing the entanglement density (i.e., the number of junction points) is supposed to limit the entropic restoring force magnitude. In this study, the influence of blend ratio of low molecular weight wax and orientation level on the mechanical properties of the thin films, especially the elastic recovery, were evaluated. Elastic energy strain recovery was calculated from hysteresis curve obtained during 60% loading (stretch) and unloading (recovery) cycle and compared to rheological and orientation measurement. It has been shown that a decrease in entanglement density can minimize elastic recovery, Nevertheless, a compromise must be found, in order to limit the permanent deformation caused by chain flow. Macromolecular orientation is also a way to adjust the film mechanical properties. A LDPE 3 × 3 biaxial orientation leads to a 25% reduction in transversal direction elastic recovery (compared to MDO cast film) without altering machine direction mechanical behavior. However, for ethylene vinyl acetate, the uniaxial macromolecular orientation seems to impact the film behavior in the transverse direction by causing a smaller inter-atom distance, favoring a higher bond strength. The latter acts as transient physical nodes, increasing entropic restoring forces.
{"title":"Entanglement density, macromolecular orientation, and their effect on elastic strain recovery of polyolefin films","authors":"Fanny Traon, Y. Grohens, Y. Corre","doi":"10.1177/87560879211058768","DOIUrl":"https://doi.org/10.1177/87560879211058768","url":null,"abstract":"For amorphous polymers, restoring forces are generated by the progressive orientation of the macromolecular chains in the stretching direction leading to a decrease in the system entropy. Orienting the chains in the future stretching direction thus reduces the entropy variation induced by the stretching and limits the entropic restoring force magnitude. Entropic restoring forces created during stretching have been correlated to the number of junction points by previous studies. Reducing the entanglement density (i.e., the number of junction points) is supposed to limit the entropic restoring force magnitude. In this study, the influence of blend ratio of low molecular weight wax and orientation level on the mechanical properties of the thin films, especially the elastic recovery, were evaluated. Elastic energy strain recovery was calculated from hysteresis curve obtained during 60% loading (stretch) and unloading (recovery) cycle and compared to rheological and orientation measurement. It has been shown that a decrease in entanglement density can minimize elastic recovery, Nevertheless, a compromise must be found, in order to limit the permanent deformation caused by chain flow. Macromolecular orientation is also a way to adjust the film mechanical properties. A LDPE 3 × 3 biaxial orientation leads to a 25% reduction in transversal direction elastic recovery (compared to MDO cast film) without altering machine direction mechanical behavior. However, for ethylene vinyl acetate, the uniaxial macromolecular orientation seems to impact the film behavior in the transverse direction by causing a smaller inter-atom distance, favoring a higher bond strength. The latter acts as transient physical nodes, increasing entropic restoring forces.","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"62 1","pages":"306 - 336"},"PeriodicalIF":3.1,"publicationDate":"2022-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90820905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-27DOI: 10.1177/87560879211066900
M. Javed, Sarah Nasir, N. Ali, S. Arshad
This paper mathematically studies calendering with a tangent hyperbolic model to simulate non-Newtonian polymers. The constitutive equations based on Lubrication Approximation Theory (LAT) are first non-dimensionalized and then simplified. The simplified equations describing the flow inside the calender are solved (a) analytically using the perturbation method and (b) numerically using MatLab built-in routine “BVP4c” method. The first case obtains an analytical expression for velocity, pressure gradient, and final sheet thickness with the help of the perturbation method, while BVP4c and Runge-Kutta methods are used to calculate the velocity, pressure, pressure gradient, and mechanical quantities numerically. The power-law index and Weissenberg number influence on pressure, pressure gradient, and velocity profiles of fluid being calendered are shown with graphs. The pressure inside the calender decreases as the power-law index and Weissenberg number increase. The force function and final sheet thickness decreases as the power-law index and Weissenberg number increases.
{"title":"Mathematical simulation of the calendering process for non-Newtonian polymers","authors":"M. Javed, Sarah Nasir, N. Ali, S. Arshad","doi":"10.1177/87560879211066900","DOIUrl":"https://doi.org/10.1177/87560879211066900","url":null,"abstract":"This paper mathematically studies calendering with a tangent hyperbolic model to simulate non-Newtonian polymers. The constitutive equations based on Lubrication Approximation Theory (LAT) are first non-dimensionalized and then simplified. The simplified equations describing the flow inside the calender are solved (a) analytically using the perturbation method and (b) numerically using MatLab built-in routine “BVP4c” method. The first case obtains an analytical expression for velocity, pressure gradient, and final sheet thickness with the help of the perturbation method, while BVP4c and Runge-Kutta methods are used to calculate the velocity, pressure, pressure gradient, and mechanical quantities numerically. The power-law index and Weissenberg number influence on pressure, pressure gradient, and velocity profiles of fluid being calendered are shown with graphs. The pressure inside the calender decreases as the power-law index and Weissenberg number increase. The force function and final sheet thickness decreases as the power-law index and Weissenberg number increases.","PeriodicalId":16823,"journal":{"name":"Journal of Plastic Film & Sheeting","volume":"49 1","pages":"369 - 395"},"PeriodicalIF":3.1,"publicationDate":"2022-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85102747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}