Morphology Development, Structure and Dielectric Properties of Biaxially Oriented Polypropylene

Abstract

This paper outlines our recent study on effects of cast film extrusion and biaxial orientation on the morphological development and dielectric performance of biaxially oriented polypropylene (PP) films based on two capacitor-grade isotactic PP (iPP) raw materials. Results on polymorphic composition, melting behavior, microstructure and dielectric properties are reported. Morphological development during film manufacturing is found to have a profound effect on film structure and dielectric characteristics. Formation of structural defects was traced back to crystal transformation upon biaxial stretching.

Compounding, Structure and Dielectric Properties of Silica-BOPP Nanocomposite Films

“…The measured εr values were generally within the expected range for BOPP [15,16], showing a slightly decreasing trend with increasing temperature from -60 °C to 125 °C. Although small differences in εr were noticed between the studied materials, it is currently challenging to assess the role of silica alone, as such variations could also be attributed to film voids [3] and/or thickness measurement inaccuracy [17]. With increasing silica content, the dielectric loss spectra (tan δ = εr ' /εr) showed (i) a slight increase of tan δ below the glass transition temperature Tg (approx.…”

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

“…8a could also be attributed to film voids (see above) or thickness measurement inaccuracy. 78 With increasing silica content, the dielectric loss spectra () showed (i) a slight increase of tan δ below the glass transition temperature T g (approx. −5 °C, see Table S1†), (ii) appearance of a new peak at ∼65 °C and (iii) reduction of dielectric loss at high temperatures.…”

“…The measured 𝜀 𝑟 values were generally within the expected range for BOPP 5,18 , showing a slightly decreasing trend with increasing temperature from -60 °C to 125 °C. Slight variation in 𝜀 𝑟 were noticed between the studied materials, which can be partly related to the HMDStreated silica 37 , however assessing the role of silica and silica-PP interface on the real permittivity is challenging, as the small differences in 𝜀 𝑟 observed in Figure 8a could also be attributed to film voids (see above) or thickness measurement inaccuracy 78 . With increasing silica content, the dielectric loss spectra (tan 𝛿 = 𝜀 𝑟 ′ /𝜀 𝑟 ) showed (i) a slight increase of tan 𝛿 below the glass transition temperature 𝑇 𝑔 (approx.…”

Effect of Fiber Morphology and Elemental Composition of Ananas comosus Leaf on Cellulose Content and Permittivity

“…A morphological study provides important information for the development of fibers with desired properties. The morphological characteristics of fibers, such as crystallinity, polarity, fiber diameters, composition, and arrangement, are important since they define the electrical, physical, chemical, and mechanical properties of the fibers [17]. The morphological features of a fiber can significantly affect the properties and performance of a material since every feature explains its effect on that material.…”