02940nas a2200313   4500008004100000022001400041245010600055210006900161260007300230300001000303490000800313520191500321653001202236653002002248653002302268653002402291653000802315653000802323653000802331100001802339700002702357700002302384700001702407700001702424700002102441700002102462700002102483856012202504       2011                        eng d  a0377-025700aExtrudate swell of linear and branched polyethylenes: ALE simulations and comparison with experiments0 aExtrudate swell of linear and branched polyethylenes ALE simulat  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN  a12-240 v1663 a<p>Extrudate swell is a common phenomenon observed in the polymer extrusion industry. Accurate prediction of the dimensions of an extrudate is important for appropriate design of dies for profile extrusion applications. Prediction of extrudate swell has been challenging due to (i) difficulties associated with accurate representation of the constitutive behavior of polymer melts, and (ii) difficulties associated with the simulation of free surfaces, which requires special techniques in the traditionally used Eulerian framework. In a previous work we had argued that an Arbitrary Lagrangian Eulerian (ALE) based finite element formulation may have advantages in simulating free surface deformations such as in extrudate swell. In the present work we reinforce this argument by comparing our ALE simulations with experimental data on the extrudate swell of commercial grades of linear polyethylene (LLDPE) and branched polyethylene (LOPE). Rheological behavior of the polymers was characterized in shear and uniaxial extensional deformations, and the data was modeled using either the Phan-Thien Tanner (PTT) model or the eXtended Pom-Pom (XPP) model. Additionally, flow birefringence and pressure drop measurements were done using a 10:1 contraction-expansion (CE) slit geometry in a MultiPass Rheometer. Simulated pressure drop and contours of the principal stress difference were compared with experimental data and were found to match well. This provided an independent test for the accuracy of the ALE code and the constitutive equations for simulating a processing-like flow. The polymers were extruded from long (L/D=30) and short (L/D=10) capillaries dies at 190 degrees C. ALE simulations were performed for the same extrusion conditions and the simulated extrudate swell showed good agreement with the experimental data. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.</p>10aALE-FEM10aextrudate swell10aFlow birefringence10aMultiPass Rheometer10aPSD10aPTT10aXPP1 aGanvir, Vivek1 aGautham, Basavarsu, P.1 aPol, Harshawardhan1 aBhamla, Saad1 aSclesi, Lino1 aThaokar, Rochish1 aLele, Ashish, K.1 aMackley, Malcolm  uhttps://library.ncl.res.in/content/extrudate-swell-linear-and-branched-polyethylenes-ale-simulations-and-comparison-002230nas a2200289   4500008004100000022001400041245010000055210006900155260005700224300001100281490000700292520129500299653001301594653001401607653000901621653001101630653001201641653001801653653001701671100002301688700001801711700002201729700002601751700001801777700002101795856012401816       2014                        eng d  a0035-451100aNonisothermal analysis of extrusion film casting process using molecular constitutive equations0 aNonisothermal analysis of extrusion film casting process using m  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcJAN  a85-1010 v533 a<p>Extrusion film casting (EFC) is a commercially important process that is used to produce several thousand tons of polymer films and coatings. In a recent work, we demonstrated the influence of polymer chain architecture on the extent of necking in an isothermal film casting operation (Pol et al., J Rheol 57:559-583, 2013). In the present research, we have explored experimentally and theoretically the effects of long-chain branching on the extent of necking during nonisothermal film casting conditions. Polyethylenes of linear and long-chain branched architectures were used for experimental studies. The EFC process was analyzed using the 1-D flow model of Silagy et al. (Polym Eng Sci 36:2614-2625, 1996) in which the energy equation was introduced to model nonisothermal effects, and two multimode constitutive equations, namely the ``extended pom-pom'' (XPP, for long-chain branched polymer melts) equation and the ``Rolie-Poly stretch version'' (RP-S, for linear polymer melts) equation, were incorporated to account for the effects of polymer chain architecture. We show that the model does a better job of capturing the qualitative features of the experimental data, thereby elucidating the role of chain architecture and nonisothermal conditions on the extent of necking.</p>10aBranched10aExtrusion10aFilm10aLinear10aNecking10aNonisothermal10aPolyethylene1 aPol, Harshawardhan1 aBanik, Sourya1 aAzad, Lal, Busher1 aThete, Sumeet, Suresh1 aDoshi, Pankaj1 aLele, Ashish, K.  uhttps://library.ncl.res.in/content/nonisothermal-analysis-extrusion-film-casting-process-using-molecular-constitutive-002207nas a2200265   4500008004100000022001400041245006400055210006400119260006700183300001400250490000700264520134600271100002501617700001801642700002201660700001901682700001901701700001801720700002301738700002001761700001801781700002301799700002101822856009801843       2015                        eng d  a0032-388800aExtrusion film casting of long chain branched polypropylene0 aExtrusion film casting of long chain branched polypropylene  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcSEP  a1977-19870 v553 a<p>Extrusion film casting (EFC) is an important melt processing operation which is extensively used to make polypropylene (PP) films. Linear PP shows significant amount of necking and draw resonance during EFC. One of the ways to reduce necking is to introduce long chain branches (LCB) on the polymer backbone. The long branches impart extensional strain hardening behavior thereby stabilizing the melt flow. In this work, we investigate the influence of long chain branching in polypropylene on the extent of necking in the EFC process. Laboratory scale EFC experiments were performed on homopolymer PP of linear and long chain branched architectures. Simulations of the EFC process were carried out using the one-dimensional flow model of Silagy et al., Polym. Eng. Sci.,36, 2614 (1996) into which we incorporate two different multi-mode molecular constitutive equations namely, the eXtended Pom-Pom' equation (XPP, for long chain branched PP) and the Rolie-Poly' equation (RP-S, for linear PP). Our experimental data confirm that presence of long chain branching in PP reduces the extent of necking and our numerical predictions show qualitative agreement with experimental data, thereby elucidating the role of chain architecture on the extent of necking. POLYM. ENG. SCI., 55:1977-1987, 2015. (c) 2014 Society of Plastics Engineers</p>1 aChikhalikar, Kalyani1 aBanik, Sourya1 aAzad, Lal, Busher1 aJadhav, Kishor1 aMahajan, Sunil1 aAhmad, Zubair1 aKulkarni, Surendra1 aGupta, Surendra1 aDoshi, Pankaj1 aPol, Harshawardhan1 aLele, Ashish, K.  uhttps://library.ncl.res.in/content/extrusion-film-casting-long-chain-branched-polypropylene-002412nas a2200265   4500008004100000022001400041245008700055210006900142260006700211300001400278490000700292520149600299100002501795700002401820700002301844700002401867700001501891700001901906700001901925700001801944700002301962700002001985700002102005856012002026       2015                        eng d  a0032-388800aLong chain branched impact copolymer of polypropylene: microstructure and rheology0 aLong chain branched impact copolymer of polypropylene microstruc  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJUL  a1463-14740 v553 a<p>A biphasic impact copolymer of polypropylene (ICP) was modified with peroxide by reactive extrusion process resulting in reduced melt flow index, improved melt strength, and higher die swell. The polymers were for the first time subjected to systematic rheological and microstructural characterization in an effort to understand their structure-property relations. In shear rheological tests, the modified ICP displayed higher flow activation energy, reduced values of loss tangent and nearly equal frequency dependence of storage and loss modulli. The modified ICP also showed strain hardening behaviour in uniaxial extensional rheology and higher crystallization temperature in differential scanning calorimetry (DSC). All these are definitive indications of the presence of long chain branches (LCB). Fitting the rheological data of modified ICPs with the eXtended Pom Pom (XPP) model indicated the presence of LCB on the higher molecular weight fraction in the polymer, a result which was corroborated with multi-detector high temperature gel permeation chromatography (HT-GPC). More importantly, the matrix and rubber phases of the ICP were separately characterized for presence of long chain branching by rheology, DSC and HT-GPC. The results indicate that while LCB existed in the matrix phase, microgels were present in both phases indicating that the reaction with peroxide occurred in both phases. POLYM. ENG. SCI., 55:1463-1474, 2015. (c) 2014 Society of Plastics Engineers</p>1 aChikhalikar, Kalyani1 aDeshpande, Anushree1 aPol, Harshawardhan1 aDhoble, Deepa, Arun1 aJha, Saroj1 aJadhav, Kishor1 aMahajan, Sunil1 aAhmad, Zubair1 aKulkarni, Surendra1 aGupta, Surendra1 aLele, Ashish, K.  uhttps://library.ncl.res.in/content/long-chain-branched-impact-copolymer-polypropylene-microstructure-and-rheology-002370nas a2200169   4500008004100000245015600041210006900197260000800266300001200274490000700286520169900293100001801992700001802010700001802028700002302046856013102069       2017                        eng d00aEffect of viscoelastic relaxation modes on stability of extrusion film casting process modeled using multi-mode Phan-Thien-Tanner constitutive equation0 aEffect of viscoelastic relaxation modes on stability of extrusio  cJUL  a487-5000 v473 aExtrusion film casting (EFC) is a commercially important process that is used to produce a significant quantity of polymer films, sheets and coatings for both industrial and household applications. Recently, we have demonstrated the influence of polymer chain architecture on the extent of necking under isothermal as well as non-isothermal film casting operation for commercially relevant polyolefin based materials [1-4]. In the present research, we focus on another instability that frequently occurs in high-speed EFC process called as draw resonance. Draw resonance manifests itself as an instability that causes periodic fluctuations in both the width as well as thickness of the extruded molten film above a critical draw ratio (DR). In this work, we have carried out a linear stability analysis of the isothermal EFC process using a multi-mode Phan-Thien-Tanner (PTT) constitutive equation to determine the onset of draw resonance. We show that as the number of relaxation modes is increased there is a dramatic change in the stability regions. In particular, there is a marked variation in the stability regions obtained by Simulating the multi-mode model and those obtained by taking averaged relaxation time of the modes. Additionally, as the number of faster-relaxing modes in a multi-mode spectrum is progressively increased, the process becomes increasingly stable as the level of elasticity in the melt decreases. Finally, the addition of a long relaxation mode in a multi-mode spectrum is akin to adding a long chain branch to a linear polymer that leads to a reduction in film necking and in many cases to enhanced process stability. (C) 2017 Elsevier Inc. All rights reserved.1 aDhadwal, Renu1 aBanik, Sourya1 aDoshi, Pankaj1 aPol, Harshawardhan  uhttps://library.ncl.res.in/content/effect-viscoelastic-relaxation-modes-stability-extrusion-film-casting-process-modeled-using02520nas a2200265   4500008004100000022001400041245014300055210006900198260000800267300001200275490000700287520162200294653001901916653001901935653001901954653001501973653001801988653001402006100002102020700002202041700002902063700002302092700001802115856012102133       2018                        eng d  a0035-451100aNon-isothermal analysis of extrusion film casting using multi-mode Phan-Thien Tanner constitutive equation and comparison with experiments0 aNonisothermal analysis of extrusion film casting using multimode  cJUL  a493-5030 v573 a<p>Extrusion film casting (EFC) is an industrially important process which produces thousands of tons of polymer films, sheets, and coating used for various industrial as well as household applications. In this paper, we focus on an instability which occurs during certain polymer processing operations operating under predominantly elongational flow, such as extrusion film casting and fiber spinning. This instability, called the draw resonance, occurs in the form of sustained periodic fluctuations in the film dimensions. It appears when the process goes beyond the critical line speed of the EFC process. In this work, a conventional linear stability analysis is carried out for nonisothermal EFC process to determine the onset of the draw resonance. The polymer rheology is modeled by the Phan-Thien Tanner (PTT) multi-mode constitutive equation. For the implementation, a conventional shooting method approach is used. Extrusion film casting experiments were also carried out using a conventional linear low-density polyethylene (LLDPE) by varying process parameters such as draw ratio and aspect ratio, to observe the effect on the stability of the process. Linear stability analysis results under non-isothermal conditions are compared and validated with existing results from literature and with our own experimental data. This work displays the effect of multiple relaxation modes as well as the temperature influence on the stability of EFC process. Finally, results also indicate that the temperature highly affects the stability of the EFC process and cannot be ignored from modeling of EFC process.</p>10aDeborah number10aDraw resonance10aFilm extrusion10aMulti-mode10aNonisothermal10astability1 aChougale, Sanket1 aRokade, Dhammaraj1 aBhattacharjee, Tanushree1 aPol, Harshawardhan1 aDhadwal, Renu  uhttps://library.ncl.res.in/content/non-isothermal-analysis-extrusion-film-casting-using-multi-mode-phan-thien-tanner00704nas a2200133   4500008004100000245010200041210006900143260004000212520012200252100002200374700002100396700002300417856013000440       2018                        eng d00a Strategies to reduce necking and drawdown defects in polymer melt extrusion film casting process0 aStrategies to reduce necking and drawdown defects in polymer mel  aBoston, MAbAMER CHEMICAL SOC.cAUG3 a256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond1 aRokade, Dhammaraj1 aChougale, Sanket1 aPol, Harshawardhan  uhttps://library.ncl.res.in/content/strategies-reduce-necking-and-drawdown-defects-polymer-melt-extrusion-film-casting-process02609nas a2200337   4500008004100000022001400041245017500055210006900230260000800299300002100307490000700328520146600335653001901801653003301820653001401853653000901867653003001876653001301906653001901919653001701938653001301955653001401968100002201982700002102004700002002025700002902045700002502074700002302099700001802122856013102140       2021                        eng d  a8756-087900aControlling draw resonance during extrusion film casting of nanoclay filled linear low-density polyethylene: an experimental study and numerical linear stability analysis0 aControlling draw resonance during extrusion film casting of nano  cJUL  a87560879209784430 v373 a<p>Commercially important extrusion film casting (EFC) processes for manufacturing plastic films or sheets are hampered by several instabilities that severely limits their productivity. In this research we focussed on one important instability: the draw resonance that occurs during the EFC process mainly under extensional flow conditions. Draw resonance is the sustained periodic oscillations in the film dimensions, notably film width and thickness, when the process operates beyond a critical draw ratio (CDR). In this research our goal was to reduce this draw resonance instability by incorporating well dispersed nanoclay fillers in a base polymeric resin (such as a linear low density polyethylene - LLDPE) to determine how these nanocomposite (NC) formulations can prevent or reduce the draw resonance defect. EFC experiments were conducted on the base resin and on the NC formulations under non-isothermal conditions to determine the onset of the draw resonance experimentally. Conventional linear stability analysis was performed to determine the onset of the draw resonance defect numerically. Numerical predictions for the onset of draw resonance were in qualitative agreement with our experimental data. Our results showed that incorporating appropriate nanoclay concentrations in a base polymeric resin indeed enhanced the EFC process stability for those polymer formulations and thus can have important economic implications for processors.</p>
10aDraw resonance10aextensional strain hardening10aExtrusion10aFilm10ahydrodynamic interactions10aNanoclay10aNanocomposites10aPolyethylene10aRheology10astability1 aRokade, Dhammaraj1 aChougale, Sanket1 aPatil, Prashant1 aBhattacharjee, Tanushree1 aGawande, Dnyaneshwar1 aPol, Harshawardhan1 aDhadwal, Renu  uhttps://library.ncl.res.in/content/controlling-draw-resonance-during-extrusion-film-casting-nanoclay-filled-linear-low-density02309nas a2200313   4500008004100000022001400041245009600055210006900151260000800220300001400228490000700242520130500249653001601554653001401570653001701584653001801601653002201619653001401641100003101655700002001686700002601706700001701732700002301749700001901772700002001791700002901811700003101840856012401871       2023                        eng d  a0032-388800aLuminescent 3D printed poly(lactic acid) nanocomposites with enhanced mechanical properties0 aLuminescent 3D printed polylactic acid nanocomposites with enhan  cJUL  a2059-20720 v633 a<p>
	The three-dimensional (3D) printing of functional composite materials has gained tremendous interest in recent years. Nevertheless, research on 3D printing of luminescent composite materials is very limited, and the mechanical properties of such 3D-printed composites are poor. Herein, we report the preparation and characterization of a poly(lactic acid) (PLA) composite that, when 3D printed, exhibits enhanced toughness and high solid-state fluorescence quantum yield. Incorporation of only 1 wt% pyrene butyric acid modified cellulose nanofibers (PBA-m-CNF) and l0 wt% thermoplastic polyurethane (TPU) into PLA led to 223% increase in toughness and 21% increase in tensile modulus of PLA. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (mu-CT) analysis of the fractured cross-sections of 3D printed composites revealed a ductile failure mode. The PLA/PBA-m-CNF1/TPU10 3D printed composite also exhibited a high solid-state fluorescence quantum yield of 38.35%. To the best of our knowledge, this is the first report to show both enhanced mechanical properties and high solid-state fluorescence emission for 3D printable PLA. Such functional PLA composites could have potential applications in the fabrication of complex-shaped sensors, optical light pipes, etc.</p>
10a3D printing10aComposite10afluorescence10aNanocellulose10apoly(lactic acid)10atoughness1 aKothavade, Premkumar, Anil1 aYadav, Prashant1 aNidhankar, Aakash, D.1 aTorris, Arun1 aPol, Harshawardhan1 aKafi, Abdullah1 aBateman, Stuart1 aSukumaran, Santosh, Babu1 aShanmuganathan, Kadhiravan  uhttps://library.ncl.res.in/content/luminescent-3d-printed-polylactic-acid-nanocomposites-enhanced-mechanical-properties02655nas a2200289   4500008004100000022001400041245013800055210006900193260000800262300001200270490000700282520171900289653001902008653001402027653000902041653001702050653002402067653002002091653001202111653001002123653002102133100002202154700002002176700002302196700002302219856012302242       2023                        eng d  a8756-087900aRheology and processing study on controlling material and process defects in polymer melt extrusion film casting using polymer blends0 aRheology and processing study on controlling material and proces  cAPR  a211-2400 v393 a<p>
	The primary objective of this research paper is to control the material and process defects in polymer melt extrusion film casting (EFC) process for linear chain architecture polyethylene (PE) resins through polymer blending methodology. Extrusion film casting is a well-known industrially important manufacturing process that is used to manufacture thousands of tons of polymer/plastic films/sheets and coated products. In this research, the necking defect in an EFC process has been studied experimentally for a linear low density polyethylene (LLDPE) resin and attempts have been made to control its necking by blending in a long chain branched (LCB) low density polyethylene (LDPE) resin. The blending methodology is based on the understanding that a LDPE resin displays enhanced resistance to necking as compared to the LLDPE resin. It is found that added LDPE resin enhances necking resistance for the primary LLDPE resin. Further, as the LDPE concentration increases in the blend formulation, the necking is further reduced as compared to pure LLDPE. Analogous to past studies on EFC of linear and long chain branched architecture containing PEs, it is observed that as the LDPE is increased in the blend formulations, the formulations displayed enhanced melt elasticity and extensional strain hardening in rheological studies. It is concluded from this study that polyethylene resins having linear chain architecture can be made amenable to enhanced resistance to necking using appropriate amount of a long chain branched resins. Finally, process defects such as the draw resonance onset could be shifted to higher draw ratios as the LDPE level is increased in the LLDPE-LDPE blend formulation.</p>
10aDraw resonance10aExtrusion10aFilm10alinear chain10along-chain branched10amelt elasticity10aNecking10aonset10astrain hardening1 aRokade, Dhammaraj1 aPatil, Prashant1 aNandimath, Sheetal1 aPol, Harshawardhan  uhttps://library.ncl.res.in/content/rheology-and-processing-study-controlling-material-and-process-defects-polymer-melt02487nas a2200277   4500008004100000022001400041245012500055210006900180260000900249300001400258490000600272520153800278653002001816653002001836653003501856653002101891653001401912100002501926700002001951700001901971700002301990700001902013700002002032700003102052856012602083       2024                        eng d  a2637-610500aEnhancing the crystallization kinetics and mechanical properties of poly(lactic acid) blends for 3D printing application0 aEnhancing the crystallization kinetics and mechanical properties  cMAY   a5754-57620 v63 a<p>
	3D printing of poly(lactic acid) (PLA) blends has been attempted to resolve issues such as inherent brittleness and slow crystallization rate of PLA. However, a persistent challenge remains in the form of phase separation or gradual migration of the blended soft polymer or plasticizers. To simultaneously enhance the miscibility of the blends and toughness of 3D-printed parts, a triblock copolymer PLA-PEG-PLA was synthesized and blended with PLA in varying proportions (5, 10, 15, and 20 wt %). Blending only 10-20 wt % low molecular weight PLA-PEG-PLA into PLA yielded a miscible blend that showed a 45-fold increase in elongation at break and a 23-fold enhancement in toughness over neat PLA. Scanning electron microscopy (SEM) images of fractured cross sections revealed a brittle to ductile transition in 3D-printed PLA/PLA-PEG-PLA samples. Isothermal crystallization studies and data analysis using the Avrami equation showed an enhancement in the crystal growth rate and overall rate of crystallization. The blends achieved half of their crystallinity in approximately 3 min, a significant improvement over the 9 min required by PLA alone. This underscores the efficiency of our approach. This was also evident in the spherulite growth of 3D-printed PLA and mPLA blends when examined using polarized optical microscopy (POM). To the best of our knowledge, this is the first report exploring the use of blends that include PLA and low molecular weight PLA-PEG-PLA triblock copolymers for 3D printing applications.</p>
10aCrystallization10aFFF 3D printing10aPLA-PEG-PLA triblock copolymer10apoly(lacticacid)10atoughness1 aKothavade, Premkumar1 aYadav, Prashant1 aGopal, Animesh1 aPol, Harshawardhan1 aKafi, Abdullah1 aBateman, Stuart1 aShanmuganathan, Kadhiravan  uhttps://library.ncl.res.in/content/enhancing-crystallization-kinetics-and-mechanical-properties-polylactic-acid-blends-3d02608nas a2200265   4500008004100000022001400041245009400055210006900149260000800218300000800226490000700234520172000241653002601961653002501987653002302012653002602035653002402061653002202085100001902107700002202126700002002148700002802168700002302196856012302219       2025                        eng d  a0250-470700aEnhancement of mechanical and rheological properties of PA-12 through silane modification0 aEnhancement of mechanical and rheological properties of PA12 thr  cDEC  a1460 v483 a<p>
	This research examines the effects of silane modifications on polyamide 12 (PA-12) to improve its mechanical and thermal properties. The study employs a reactive extrusion technique to integrate various silanes-Dynasylan (R) AMEO, Dynasylan (R) 1189, Dynasylan (R) DAMO and Dynasylan (R) VPS 4721-at different concentrations (0.25, 0.5 and 0.75%). Key findings reveal that silane modifications significantly enhance the tensile strength, impact resistance and viscoelastic behaviour of PA-12, with the Dynasylan (R) DAMO formulation achieving the highest tensile strength of 38.25 MPa vis-&amp; agrave;-vis 8.02 MPa for PA-12. The modifications also resulted in a reduction of crystallinity by over 35%, contributing to improved toughness and impact strength. Rheological assessments indicate that the flow properties of PA-12 are positively altered, enhancing its complex viscosity and storage modulus, which are crucial for applications in automotive and aerospace industries. Thermal analysis through differential scanning calorimetry and thermogravimetric analysis confirms improved thermal stability, particularly in the 0.5% Dynasylan (R) AMEO-modified sample, exhibiting an onset temperature of 421.87 degrees C. The study emphasizes the importance of the silane type and dosage in tailoring PA-12's performance for advanced applications, suggesting future research directions to further refine silane-modification techniques for enhanced polymer performance. This research provides valuable insights into polymer-modification strategies, highlighting the potential for silane treatments to optimize the mechanical, thermal and rheological properties of PA-12 for diverse industrial applications.</p>
10amechanical properties10aPolyamide 12 (PA-12)10areactive extrusion10arheological behaviour10asilane modification10athermal stability1 aJadhav, Pravin1 aMahajan, Digvijay1 aPatil, Prashant1 aUmbarkar, Shubhangi, B.1 aPol, Harshawardhan  uhttps://library.ncl.res.in/content/enhancement-mechanical-and-rheological-properties-pa-12-through-silane-modification02707nas a2200241   4500008004100000022001400041245011300055210006900168260000900237300001400246490000600260520184600266653002002112653002002132653006402152653001402216653001202230100001902242700002002261700002302281700003102304856013002335       2025                        eng d  a2637-610500aUpcycling of postconsumer recyclate polypropylene into low warping and high toughness 3D printable filaments0 aUpcycling of postconsumer recyclate polypropylene into low warpi  cJUN   a7373-73810 v73 a<p>
	Polypropylene (PP) is widely used in commodity applications owing to its chemical stability, mechanical properties and low cost. However, almost 50% of the produced PP ends up as postconsumer waste (PCW) within a short period of usage. Being a non-biodegradable polymer, recycling PCW PP is important to mitigate plastic waste in landfills. Nonetheless, recycling or upcycling postconsumer recyclate (PCR) PP into valuable resources without deterioration in physical and mechanical properties is a challenge. This report presents an approach to upcycle PCR polypropylene (rPP) into high quality 3D printing filament that not only prints with very low warpage but with significantly high elongation at break and toughness. Incorporation of poly(butylene adipate-co-terephthalate) (PBAT) along with maleic anhydride grafted polypropylene (MAPP) in specific proportions led to a significant enhancement in mechanical properties, miscibility, crystallization behavior, and 3D printability. rPP/PBAT blends with 20 wt % PBAT and 10 wt % MAPP exhibited a 62-fold enhancement in elongation at break over rPP (from 1.88 to 118.29%) and a 72-fold increase in toughness (from 2 to 143.60 kJ/m3) with almost similar tensile strength. The final printed components had better layer adhesion and structural stability with a dramatic decrease in warpage, from 25.82% for pristine rPP to only 7.86% for rPP/PBAT blend. Isothermal crystallization studies and data analysis using the Avrami equation showed that crystallization half-time (t 1/2), which measures the duration needed for half of the total crystallinity to form, increased from 12.6 s for rPP to 66 s for the rPP/PBAT blend. This report demonstrates an approach to upcycle PCR PP, a positive step toward realizing the goals of circular economy and sustainable additive manufacturing.</p>
10aCrystallization10aFFF 3D printing10apolypropylene/poly(butylene adipate-co-terephthalate)blends10atoughness10awarpage1 aGopal, Animesh1 aPatil, Prashant1 aPol, Harshawardhan1 aShanmuganathan, Kadhiravan  uhttps://library.ncl.res.in/content/upcycling-postconsumer-recyclate-polypropylene-low-warping-and-high-toughness-3d-printable02655nas a2200289   4500008004100000022001400041245008500055210006900140260000800209490000800217520171400225653001601939653003101955653002201986653001602008653001302024100002902037700002502066700001802091700002302109700002002132700002202152700002302174700003102197700001702228856012002245       2026                        eng d  a1022-135200aVanillin-based recyclable thermosets and their glass fiber reinforced composites0 aVanillinbased recyclable thermosets and their glass fiber reinfo  cJAN0 v2273 a<p>
	The accumulation of end-of-life plastic materials and composite reinforcement waste materials has brought much attention to developing sustainable alternatives and their re-processability. Incorporating covalent adaptable networks (CANs) into the crosslinked network bridges the concept of reversibility into the otherwise conventional non-reversible networks. This study investigates the structure-property relation in two reversible hardener systems derived from vanillin using Schiff base chemistry. The ``CAN'' systems were synthesized by condensation of vanillin with two amines, 4,4'-oxydianiline and tris(2-aminoethyl)amine, respectively, to form Va_ODA and Va_TAEA. The epoxy thermosets exhibited glass transition temperatures (T-g) of 125 degrees C and 115 degrees C, respectively, for Va_ODA and Va_TAEA, which is superior to most reversible vanillin-based systems reported. The vitrimer-thermosets exhibited promising mechanical and thermal properties, and reshaping abilities as a function of applied temperatures, indicating the dynamic nature of linkages. Chemical degradability was demonstrated by heating to 80 degrees C for 12 h in aqueous acidic medium or excess amine. The fabricated glass fiber composites exhibited good mechanical properties with tensile strength of 361 MPa and degradability in acetic acid/water mixture with a fiber recovery of &gt;98 %. The recovered glass fiber exhibited almost similar tensile strength as the virgin glass fiber, demonstrating its potential reusability. The epoxy vitrimers underwent mechanical reprocessing through hot-pressing, as well as chemical reprocessing via 3D printing and by regeneration of imine bonds to form an epoxy resin.</p>
10a3D printing10acovalent adaptable network10are-processability10aSchiff base10aVanillin1 aVeetil, Ashwani, Puthiya1 aRavikumar, Aniruddha1 aRajput, Tejas1 aSingh, Aman, Kumar1 aThakur, Tamanna1 aKrishna, Abhijith1 aPol, Harshawardhan1 aShanmuganathan, Kadhiravan1 aAsha, S., K.  uhttps://library.ncl.res.in/content/vanillin-based-recyclable-thermosets-and-their-glass-fiber-reinforced-composites