Comparatively Thermal and Crystalline Study of Poly(methyl‐methacrylate)/Polyacrylonitrile Hybrids: Core–Shell Hollow Fibers, Porous Fibers, and Thin Films

Abstract

The polyacrylonitrile/polymethyl-methacrylate (PMMA/PAN) porous fibers, core–shell hollow fibers, and porous thin films are prepared by coaxial electrospinning, single electrospinning, and spin-coating technologies, respectively. The different morphologies arising from different processes display great influences on their thermal and crystalline properties. The adding of PMMA causes porous structure due to the microphase-separation structure of immiscible PMMA and PAN phases. The lower weight loss, higher degradation temperature, and glass-transition temperatures of porous thin films than those of porous fibers and core–shell hollow fibers are obtained, evidencing that the polymer morphologies produced from the different process can efficiently influence their physical properties. The orthorhombic structure of PAN crystals are found in the PMMA/PAN porous thin films, but the rotational disorder PAN crystals due to intermolecular packing are observed in the PMMA/PAN porous fibers and core–shell hollow fibers, indicating that different processes cause different types of PAN crystals.

Influence of Working Temperature on The Formation of Electrospun Polymer Nanofibers

“…A synthetic and semicrystalline organic polymer resin with the linear formula (C 3 H 3 N) n , PAN is a versatile polymer used to produce a large variety of products, including ultrafiltration membranes, hollow fibers for reverse osmosis, and fibers for textiles. This polymer is used as the chemical precursor in 90% of high-quality carbon fiber production and is also extensively used in electrospinning; PAN nanofibers are good precursors for preparing carbon nanotubes (CNTs) [23, 24]. PVP is a water-soluble polymer made from the monomer N -vinylpyrrolidone.…”

Fabrication of electrospun fibers from a waterborne soy‐based polyurethane employing polyethylene oxide as a coformer

“…On the other hand, PEO‐PU4 and PU4 fibers as well as PU film showed a two‐step degradation responding to a typical PU decomposition pattern 32 . In the first stage (from 180 to 360°C), which was assigned to degradation of urethane bonds, it stands out that the maximum rate for PU film (330°C) occurred at a higher temperature than for PEO‐PU4 and PU4 fibers (318°C), and this could be assigned to morphological issues, as it has been reported for other polymers that morphology considerably affects degradation temperature 33 . Regarding the second stage, which occurred immediately after the first one and corresponded to decomposition of the soft segment in the remaining PU structure—mainly the fatty carbon chain from the soy‐based polyol 34 —maximum rates were similar for PU4 fibers and PU film (about 450°C), while for PEO‐PU4 fibers it occurred at a considerable lower temperature (430°C), closer to the one at which PEO fibers degraded the most.…”

Self‐regulation in chemical and bio‐engineering materials for intelligent systems

“…Various methods have been used to regulate characteristics of materials in both the chemical and chemical engineering industries in recent years [1][2][3][4][5][6], which regulate the hydrophobic [7][8][9][10], antibiotic [11][12][13][14][15], radical polymerisation [16][17][18][19][20], electrical conductivity [21][22][23], thermal conductivity [23,24], and mechanochemical properties [25][26][27][28][29][30][31] within porous, biological, polymer, and photoelectric materials. The materials, which have the ability to regulate above characteristics, could be allowed to be utilised in many different and innovative applications [32][33][34]. Moreover, these applications will have very positive impacts and change their respective industries [35][36][37][38].…”