Isothermal crystallization kinetics of AB3 hyperbranched polymer (HBP)/polypropylene (PP) blends

Liu, Guangtian; Zhao, Minshou

doi:10.1007/s00289-009-0128-x

Cited by 5 publications

(9 citation statements)

References 15 publications

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“…While Boltorn-H20 effectively promoted the interfacial adhesion between PP and glass fibers, Boltorn H-30 acted as a processing aid by smoothening the surface of composites after injection molding or extrusion owing to the low viscosity of HBP. In another study, Liu and Zhao observed that 5% of hyperbranched polyamide ester in isotactic PP resulted in remarkable acceleration in the crystallization rate in PP . The fractal globular shape of HBP resulted in reduced viscosity and chain entanglement that eventually promoted the movement of polymeric chains toward the growth of nuclei.…”

Section: Introductionmentioning

confidence: 99%

“…In another study, Liu and resulted in remarkable acceleration in the crystallization rate in PP. 8 The fractal globular shape of HBP resulted in reduced viscosity and chain entanglement that eventually promoted the movement of polymeric chains toward the growth of nuclei. Hong et al observed that functionalized Boltorn H-30 acted as a lubricant in the LLDPE extrusion process by migrating toward the outer surface of the polymer to aid in overall processability.…”

Section: ■ Introductionmentioning

confidence: 99%

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Tuning Melt Strength and Processability of Polyolefins by Addition of a Functionalized Additive Designed via the TEMPO-Driven Thiol-ene Reaction

Jaisingh

Kapur

Nebhani

2021

Ind. Eng. Chem. Res.

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Thiol-ene chemistry with TEMPO as an initiator has been utilized to synthesize a first-generation dendrimer having eight peripheral hydroxyl groups. Long chain branched impact copolymer polypropylene (ICP) and linear low-density polyethylene (LLDPE) were prepared by a postreactor modification process by a meltgrafting dendrimer onto a polyolefin chain using peroxide and maleic anhydride as a co-agent. Long chain branching in ICP controlled the chain scission initiated by peroxide by increasing entanglement, while for LLDPE, it controlled the excessive crosslinking because of peroxide. Neat and modified ICP and LLDPE samples were analyzed by FT-IR, TGA, DSC, HT-GPC, MFI, and parallel-plate rheometry as well as for their melt strength. The presence of long chain branching was mainly confirmed by time−temperature superposition (TTS) analysis obtained using a parallel-plate rheometer. In comparison to neat polymers, modified ICP and LLDPE samples showed higher values of Arrhenius flow activation energy. In the case of ICP, higher processability was observed for a dendrimer-grafted sample, while modified LLDPE samples exhibited higher melt strength as compared to neat polymers. Van Gurp−Palmen plots showed a decrease in phase angle as a function of angular frequency for modified ICP and LLDPE samples, which also confirmed their thermorheological complex behavior.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Tuning Melt Strength and Processability of Polyolefins by Addition of a Functionalized Additive Designed via the TEMPO-Driven Thiol-ene Reaction

Jaisingh

Kapur

Nebhani

2021

Ind. Eng. Chem. Res.

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“…Therefore, this study has been dedicated to the investigation of the thermal properties of some molecularly modified PLAs: a neat PLA was melt strengthened through reactive extrusion with an epoxy‐based chain extender (CE). The thermal properties of those modified materials were expected to differ from the neat PLA as the molecular weight and the branching structure of a semicrystalline polymer are known to influence its thermal behavior . Several investigations based on branched/extended materials have highlighted the positive influence of this kind of chain modification on the crystallization kinetics of polymers.…”

Section: Introductionmentioning

confidence: 99%

Influence of the chain extension on the crystallization behavior of polylactide

et al. 2013

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International audienceA semicrystalline poly(lactic acid) (PLA) was modified with the help of an epoxy-based chain extender (CE) during reactive extrusion. Different amounts of CE were used resulting in samples with increased and broadened molar mass distributions as revealed by size exclusion chromatography. Thermal properties were then investigated using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). On one hand, the thermal ramps performed with DSC revealed that the glass transition was not modified by the chain extension process. On the other hand, thecrystallization behavior was found to be highly impacted by this molecular modification. Decreases in the cold crystallization temperatures Tcc and in the melting temperatures Tm occurred when the CE content was raised. Isothermal crystallizations from the melt were performed using both DSC and POM. It revealed that the overall crystallization process was significantly faster for the chain-extended PLAs while crystalline ratios were lowered. An improvement of the nucleation process coupled with a reduced crystal growth was assumed to be responsible for this change

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“…The polarized light optical microscopy analysis showed reduced spherulite size and an increase in the number of effective nuclei, which further supported the obtained results. 73 Hao and co-workers prepared graphene oxide grafted with hyperbranched polyester (GO-HBP) (as shown in Scheme 3) and compared the crystallization kinetics of isotactic PP composites with graphene oxide (iPP/GO) and with HBPgrafted graphene oxide (iPP/GO-HBP). 74 Results from differential scanning calorimetry (DSC) and polarized light optical microscopy revealed a higher rate of crystallization; nucleation as well as the growth of crystals were achieved with GO-HBP in comparison to graphene oxide.…”

Section: Nucleating Agentsmentioning

confidence: 99%

“…In another study, Liu et al investigated the isothermal crystallization kinetics behavior of hyperbranched poly(amideester) (structure shown in Figure 8b) in isotactic PP. 72 They observed that 5% of HBP in PP resulted in a remarkable acceleration in crystallization rate and the number of nuclei. The results established HBP as an effective heterogeneous nucleating agent for PP.…”

Section: Nucleating Agentsmentioning

confidence: 99%

Dendrimers and Hyperbranched Polymers as Promising and Versatile Additives in Polyolefins

Jaisingh,

Nebhani

2024

ACS Appl. Eng. Mater.

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Hyperbranched polymers (HBPs) are globular macromolecules with nonuniformly grown branches terminating in functional groups. Dendrimers are like HBPs but have a perfectly oriented structure with branches arising from the central core in a uniform fashion. The numerous functional groups present in dendrimers and HBPs can be tailored by organic modification for catering to specific applications. Over the years, these macromolecules have been tested as additives for polyolefins, particularly polypropylene (PP) and polyethylene (PE). PP and PE are the most consumed types of plastics today because of their attractive properties, such as low cost, lightweight, good chemical and electrical resistance, etc. To utilize polyolefins to their maximum potential, certain external agents called additives are incorporated in polyolefin matrices to make them more functional for engineering applications. Dendrimers and HBPs have been extensively known and acknowledged for their applications in drug delivery, wastewater treatment, bioimaging, catalysis, etc. This review exclusively accounts for the role of dendrimers and HBPs as additives in polyolefins, including processing aids, nucleating agents, flame retardants, and antioxidants, to improve thermoxidative and color stability, dyeability, and paintability, as well as mechanical, rheological, and barrier properties of polyolefins. We also review the role of unique architecture and characteristics of HBPs and dendrimers in having an edge over their analogous linear counterparts in improving multiple polyolefin properties simultaneously and their ability to increase the efficiency of conventional additives.

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Isothermal crystallization kinetics of AB3 hyperbranched polymer (HBP)/polypropylene (PP) blends

Cited by 5 publications

References 15 publications

Tuning Melt Strength and Processability of Polyolefins by Addition of a Functionalized Additive Designed via the TEMPO-Driven Thiol-ene Reaction

Tuning Melt Strength and Processability of Polyolefins by Addition of a Functionalized Additive Designed via the TEMPO-Driven Thiol-ene Reaction

Influence of the chain extension on the crystallization behavior of polylactide

Dendrimers and Hyperbranched Polymers as Promising and Versatile Additives in Polyolefins

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