Dielectric properties dependent on crystalline morphology of PP film for HVDC capacitors application

Xu, R. R.; Du, B. X.; Xiao, Mi; Liu, H.L.; Ran, Z. Y.; Xing, J. W.

doi:10.1016/j.polymer.2020.123204

Cited by 34 publications

(15 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We note here several recent studies, aimed for capacitor applications, where the beneficial role of crystallization conditions 51 or nucleating additives (e.g. βnucleating agents [52][53][54] ) are highlighted for controlling the density and nature of the crystalline-amorphous interface and improving dielectric properties of PP. However, it is important to consider that during biaxial stretching of PP-a critical conversion step to obtain thin high-performance BOPP dielectric film 43,55 -biaxial-stretching-induced transformation of the mixed α/β-spherulitic precursor film morphology into a complex BOPP fibrillar morphology with predominantly αcrystalline structure occurs, and thus it is not always straightforward to relate the effects of crystalline modification on prototypical PP specimens with BOPP film properties.…”

Section: Cast Film Propertiesmentioning

confidence: 99%

Biaxially oriented silica–polypropylene nanocomposites for HVDC film capacitors: morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

et al. 2022

View full text Add to dashboard Cite

show abstract

Section: Cast Film Propertiesmentioning

confidence: 99%

Biaxially oriented silica–polypropylene nanocomposites for HVDC film capacitors: morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Studies have shown that the discharge channels preferentially develop in the spaces between spherulites with looser structures and larger mean free paths [15]. The addition of nucleating agents can increase the spherulite density of PP, thereby limiting the transport of carriers and improving the breakdown strength [15,16]. The long-chain branch structures in LCBPP have two different effects on crystalline properties.…”

Section: Introductionmentioning

confidence: 99%

Crystallisation regulation of long‐chain branched polypropylene on dielectric performance and energy density for metallised film capacitors

Xiao

Zhang

2023

High Voltage

View full text Add to dashboard Cite

The degradation of dielectric properties of polypropylene (PP) at high temperature affects the operational stability of metallised film capacitors. This study presents a method to improve the high‐temperature dielectric performance of PP through long‐chain branching modification and regulating the crystalline properties. Different amounts of nucleating agents were added to long‐chain branched polypropylene (LCBPP) to study the effect of crystallisation on electrical properties. The results show that the long‐chain branches improve thermal stability by enhancing the chain entanglement, and also increase the number of crystals due to heterogeneous nucleation. The addition of nucleating agents promotes the crystallisation of LCBPP, which increases the nucleation density and improves the crystallinity. The regulation of the microstructure of PP suppresses the relaxation of the chains and limits the charge transport. The dielectric constant of the modified films with long‐chain branching is slightly increased, and the doping of nucleating agents has little effect on the dielectric constant and loss of LCBPP. At 125°C, the conductivity of the modified LCBPP films with the addition of 0.05 wt% nucleating agent decreased by 2 orders of magnitude and the breakdown strength increased by 26.3%. This study has implications for improving the dielectric properties of PP films.

show abstract

“…Therefore, the breakdown strength of PP decreases as the temperature increases. Studies have shown that designing the molecular chain structures by grafting and adjusting the crystalline morphology by adding nucleating agents can improve the breakdown strength of PP at high temperatures [11,15]. Compared with linear PP, long-chain branched polypropylene (LCBPP) is characterized by high melt strength and tensile strain hardening [16,17].…”

Section: Introductionmentioning

confidence: 99%

Breakdown strength improvement of polypropylene by introducing long-chain branched structures for film capacitors

Xiao¹,

Zhang²,

Du³

et al. 2022

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The breakdown strength of polypropylene (PP) for film capacitors drops sharply in a high-temperature environment, which would lead to capacitor insulation failure frequently. This paper proposes a method to improve the breakdown strength of PP at high temperatures by introducing long-chain branches (LCBs). Different from traditional linear PP, the results show that LCBs can increase the number of spherulites and refine the grains due to heterogeneous nucleation, resulting in a reduction in weak areas in the films and an increase in trap densities and energy levels in long-chain branched polypropylene (LCBPP). In addition, the higher melt strength of LCBPP indicates that LCBs promote entanglement between molecular chains and hinder the sliding of chains, thereby reducing the influence of temperature on the free volume. Therefore, compared with PP, the conductivity of LCBPP is lower at high temperatures, and the breakdown strength increases by 16.2% at 105°C. This method provides an idea for improving the breakdown strength of PP films at elevated temperatures from the perspective of regulating the microstructure.

show abstract

Dielectric properties dependent on crystalline morphology of PP film for HVDC capacitors application

Cited by 34 publications

References 26 publications

Biaxially oriented silica–polypropylene nanocomposites for HVDC film capacitors: morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

Biaxially oriented silica–polypropylene nanocomposites for HVDC film capacitors: morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

Crystallisation regulation of long‐chain branched polypropylene on dielectric performance and energy density for metallised film capacitors

Breakdown strength improvement of polypropylene by introducing long-chain branched structures for film capacitors

Contact Info

Product

Resources

About