Influence of β‐nucleation on polymorphism and properties in random copolymers and terpolymers of propylene

Benavente, Rosario; Caveda, Susana; Pérez, Ernesto; Blázquez, Enrique; Peña, Begoña; Grieken, Rafael van; Suárez, Inmaculada

doi:10.1002/pen.23322

Cited by 12 publications

(11 citation statements)

References 64 publications

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“…While the stiffness and strength of these polymers is comparably low, they are highly transparent and their broad melting range makes them suitable for sealing applications in the packaging area. [153,154] In addition to the macromolecular structure, the processing and in particular the cooling conditions are parameters that should be taken into consideration for controlling the final material properties.…”

Section: 𝜶-Olefinsmentioning

confidence: 99%

Catalyst Type Effects on Structure/Property Relations of Polypropylene Random Copolymers

Paulik

Tranninger

Wang

et al. 2021

Macro Chemistry & Physics

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Polypropylene (PP) random copolymers are an important class of commercial materials that can be tuned for a wide range of different applications. The structure-property relations are mainly discussed in this article focusing on two major influencing factors, the catalyst system and the type and amount of comonomer. Ziegler-Natta (ZN) catalyst systems still dominate the production of polypropylene and todays sixth-generation ZN catalysts are based on postphthalate donor systems. Metallocene (MC) catalysts offer possibilities to exactly control the microstructure of the polymer even better. Mostly, ethylene is used as comonomer being randomly distributed for up to 7.3 mol% when using ZN catalysts. For single site catalysts, homogenous (single phase) materials can be achieved up to ethylene contents of 20.8 mol%. The incorporated comonomer reduces the crystallization speed and the lamellar thickness of the polymer thus affording soft and highly transparent materials. Random copolymers and terpolymers with higher 𝜶-olefins only play a minor role but offer an additional possibility for property adjustments. PP random copolymers can also be varied in their performance through multistage polymerizations, altering the comonomer content and or the molecular weight in the different polymerization reactors.

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Section: 𝜶-Olefinsmentioning

confidence: 99%

Catalyst Type Effects on Structure/Property Relations of Polypropylene Random Copolymers

Paulik

Tranninger

Wang

et al. 2021

Macro Chemistry & Physics

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“…This situation has limited the number of commercial applications of b nucleated polypropylene. 12,13 Recent advances in the technology of metallocene catalysis, including the possibility of reducing their price and increasing their activity, have led to the development of very competitive polyolefins, not only by their low production cost but also by exhibiting certain properties that can replace in many applications the conventional ones. 14,15 The use of the metallocenes allows synthesizing iPP of high molecular weight that can crystallize mainly in the g-form.…”

Section: Introductionmentioning

confidence: 99%

“…This situation has limited the number of commercial applications of β nucleated polypropylene. 12,13…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

Belkouicem¹,

Benarab²,

Krache³

et al. 2018

Journal of Elastomers & Plastics

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The influence of two thermal treatments on the structure, morphology, and ultimate properties exhibited by isotactic polypropylene (iPP), synthesized by conventional Ziegler–Natta iPP (Z-iPP) or metallocene iPP (m-iPP) catalysts, has been investigated in the present work. Novelty of this research consisted in the incorporation of a β nucleating agent in two different contents to the m-iPP. Results attained are compared with those found in the Z-iPP and important differences are observed. Differential scanning calorimetry and X-ray diffraction experiments revealed that coexistence of different crystalline lattices took place depending on the type of iPP: β and α forms were found in the β nucleated Z-iPP specimens, whereas α, β, and γ polymorphs could be developed in the m-iPP with nucleating agent. On the other hand, the iPP glass transition temperature ( Tg) did not exhibit a significant change because of the addition of β nucleant, as deduced from Dynamic Mechanical Thermal Analysis (DMTA) analysis. Moreover, the size and shape of the iPP spherulites was totally changed by the presence of the β agent. This nucleant promoted the formation of smaller spherulites in a greater amount, as demonstrated by optical microscopy. Concerning the mechanical parameters, microhardness, MH, and Young modulus, E, values were in the fast crystallized samples lower than those presented by their slowly cooled counterparts. A good balance in properties was seen for the slowly crystallized m-iPP that incorporated a 5 wt% content in β nucleating agent, this fact being ascribed to the coexistence of the three α, β, and γ polymorphs.

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“…A high percentage of β‐crystals can be obtained via a nonisothermal crystallization in appropriate temperature gradients and/or via a certain shear‐induced crystallization . Besides, it is generally recognized that adding β‐nucleating agents (β‐NAs) is the most practical approach to effectively induce the formation of β‐crystals . For example, a β‐nucleated propylene‐ethylene random polypropylene copolymer (Beta‐PPR ™ ) has been well‐developed by Borealis Company.…”

Section: Introductionmentioning

confidence: 99%

Synergistic effects of α/β-nucleating agents on propylene-ethylene random copolymer: New clues for the pipe extrusion

et al. 2016

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Adding b-nucleating agents (b-NAs) has been generally considered as an effective approach to induce the formation of b-crystals in propylene-ethylene random copolymer (PPR). However, it is still difficult to obtain the expected percentage of b-crystal under normal processing conditions, due to the temperature control is always a key factor no matter with or without adding b-NAs. We assumed that simultaneously adding both a-and b-NAs to PPR in rational ratios would facilitate the growth of b-crystal. The effects of adding various amount of a-and/or b-NAs on the a-and b-crystallization behavior and morphology were investigated. More importantly, the influence of temperature control on inducing b-crystal in the presence of different NAs was parallel explored by utilizing sample bars prepared via injection molding and sample pipes produced from a typical industrial extrusion line. Different crystallization situations were carefully discussed in response to various nonisothermal crystallization processes in laboratory experiments and in actual pipes extrusion. At last, the mechanical properties of PPR samples were examined to provide new clues for further study of PPR pipes.

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Influence of β‐nucleation on polymorphism and properties in random copolymers and terpolymers of propylene

Cited by 12 publications

References 64 publications

Catalyst Type Effects on Structure/Property Relations of Polypropylene Random Copolymers

Catalyst Type Effects on Structure/Property Relations of Polypropylene Random Copolymers

Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

Synergistic effects of α/β-nucleating agents on propylene-ethylene random copolymer: New clues for the pipe extrusion

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