Crystallinity-Based Product Design: Utilizing the Polymorphism of Isotactic PP Homo- and Copolymers

Gahleitner, Markus; Mileva, Daniela; Androsch, René; Gloger, Dietrich; Tranchida, Davide; Sandholzer, Martina; Doshev, Petar

doi:10.3139/217.3242

Cited by 27 publications

(14 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this concentration range the peak temperature of PP/DMDBS decreases. The step in the peak temperature could be caused by the formation of a nanostructured network of the nucleating agents which changes the character of the main crystallization process and could be related to the formation of shish‐kebab‐like structure as is found for PP/DMDBS and PP/TBPMN . Process 4 occurs only at high content of TBPMN and at high temperatures; its dependence on content shows no clear trend.…”

Section: Resultsmentioning

confidence: 96%

Non‐isothermal crystallization of polypropylene with sorbitol‐type nucleating agents at cooling rates used in processing

Schawe

Budde

Alig

2018

Polymer International

View full text Add to dashboard Cite

Sorbitol‐type nucleating agents used as clarifiers for polypropylene (PP) show a complex interplay of phase and crystallization behavior. To study the crystallization behavior, cooling measurements were performed by fast scanning calorimetry using rates between 10 and 4000 K s−1. These rates correspond to cooling rates used in processing. These measurements were combined with conventional differential scanning calorimetry (DSC) measurements at 10 K min−1. The optical properties were characterized by haze measurements. For this investigation the commercially available clarifiers 1,3:2,4‐bis(3,4‐dimethylbenzylidene)sorbitol and 1,2,3‐tridesoxy‐4,6:5,7‐bis‐O‐[(4‐propylphenyl)methylene]nonitol were added to PP in various amounts up to 0.6 wt%. At relatively slow cooling rates only a single crystallization process was observed. In contrast, fast cooling leads to a complex crystallization behavior with up to four different crystallization processes. It was found that the temperature of the main crystallization process during fast cooling correlates with the optical properties from haze measurements. Finally, the cooling rate dependence of the different crystallization processes is discussed in terms of nucleating efficiency of the clarifiers. We conclude that the results of conventional DSC measurements cannot be extrapolated in a simple way to describe the nucleation activity of nucleating agents at cooling conditions relevant during processing. © 2018 Society of Chemical Industry

show abstract

Section: Resultsmentioning

confidence: 96%

Non‐isothermal crystallization of polypropylene with sorbitol‐type nucleating agents at cooling rates used in processing

Schawe

Budde

Alig

2018

Polymer International

View full text Add to dashboard Cite

show abstract

“…Thermal stability and the amount of filler in the different compositions used in this study were Polypropylene has a very rich polymorphism and it has been reported that filler inclusion has an effect of the overall morphology of filled systems [39]. The iPP used in this work shows generally a large tendency to form crystals in β phase, mostly due to the high purity of this system [66]. The presence of β phase for the pure material is clearly observed from the [300]β peak in Figure 9.…”

Section: Thermal Propertiesmentioning

confidence: 88%

Melt-Mixed 3D Hierarchical Graphene/Polypropylene Nanocomposites with Low Electrical Percolation Threshold

et al. 2019

View full text Add to dashboard Cite

Graphene-based materials are a family of carbonaceous structures that can be produced using a variety of processes either from graphite or other precursors. These materials are typically a few layered sheets of graphene in the form of platelets and maintain some of the properties of pristine graphene (such as two-dimensional platelet shape, aspect ratio, and graphitic bonding). In this work we present melt mixed graphene-based polypropylene systems with significantly reduced percolation threshold. Traditionally melt-mixed systems suffer from poor dispersion that leads to high electrical percolation values. In contrast in our work, graphene was added into an isotactic polypropylene matrix, achieving an electrical percolation threshold of~1 wt.%. This indicates that the filler dispersion process has been highly efficient, something that leads to the suppression of the β phase that have a strong influence on the crystallization behavior and subsequent thermal and mechanical performance. The electrical percolation values obtained are comparable with reported solution mixed systems, despite the use of simple melt mixing protocols and the lack of any pre or post-treatment of the final compositions. The latter is of particular importance as the preparation method used in this work is industrially relevant and is readily scalable.

show abstract

“…Furthermore, due to the 3D hierarchical filler morphology and subsequent filler distortions during the preparation stage, the ability to access the primary graphene particle from mechanical point of view needs to be tested. The filler has also been shown to have strong nucleation effects [27,56], resulting in an alteration of the crystalline structure, that can have a significant impact on the mechanics of the system. In this context, we focus on dynamic, tensile, impact, and creep properties of the novel 3D hierarchical reduced graphene oxide.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior of Melt-Mixed 3D Hierarchical Graphene/Polypropylene Nanocomposites

et al. 2020

View full text Add to dashboard Cite

The mechanical properties of novel low percolation melt-mixed 3D hierarchical graphene/polypropylene nanocomposites are analyzed in this study. The analysis spans a broad range of techniques and time scales, from impact to tensile, dynamic mechanical behavior, and creep. The applicability of the time–temperature superposition principle and its limitations in the construction of the master curve for the isotactic polypropylene (iPP)-based graphene nanocomposites has been verified and presented. The Williams–Landel–Ferry method has been used to evaluate the dynamics and also Cole–Cole curves were presented to verify the thermorheological character of the nanocomposites. Short term (quasi-static) tensile tests, creep, and impact strength measurements were used to evaluate the load transfer efficiency. A significant increase of Young’s modulus with increasing filler content indicates reasonably good dispersion and adhesion between the iPP and the filler. The Young’s modulus results were compared with predicted modulus values using Halpin–Tsai model. An increase in brittleness resulting in lower impact strength values has also been recorded.

show abstract

Crystallinity-Based Product Design: Utilizing the Polymorphism of Isotactic PP Homo- and Copolymers

Cited by 27 publications

References 55 publications

Non‐isothermal crystallization of polypropylene with sorbitol‐type nucleating agents at cooling rates used in processing

Non‐isothermal crystallization of polypropylene with sorbitol‐type nucleating agents at cooling rates used in processing

Melt-Mixed 3D Hierarchical Graphene/Polypropylene Nanocomposites with Low Electrical Percolation Threshold

Mechanical Behavior of Melt-Mixed 3D Hierarchical Graphene/Polypropylene Nanocomposites

Contact Info

Product

Resources

About