There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Biocomposites reinforced with natural fibers: 2000–2010

https://cyberleninka.org/article/n/768408.pdf

Mechanical properties of graphene and graphene-based nanocomposites

Natural fibers are getting attention from researchers and academician to utilize in polymer composites due to their ecofriendly nature and sustainability. The aim of this review article is to provide a comprehensive review of the foremost appropriate as well as widely used natural fiber reinforced polymer composites (NFPCs) and their applications. In addition, it presents summary of various surface treatments applied to natural fibers and their effect on NFPCs properties. The properties of NFPCs vary with fiber type and fiber source as well as fiber structure. The effects of various chemical treatments on the mechanical and thermal properties of natural fibers reinforcements thermosetting and thermoplastics composites were studied. A number of drawbacks of NFPCs like higher water absorption, inferior fire resistance, and lower mechanical properties limited its applications. Impacts of chemical treatment on the water absorption, tribology, viscoelastic behavior, relaxation behavior, energy absorption flames retardancy, and biodegradability properties of NFPCs were also highlighted. The applications of NFPCs in automobile and construction industry and other applications are demonstrated. It concluded that chemical treatment of the natural fiber improved adhesion between the fiber surface and the polymer matrix which ultimately enhanced physicomechanical and thermochemical properties of the NFPCs.

/pdf/a-review-on-natural-fiber-reinforced-polymer-composite-and-24eoqfvi7o.pdf

A Review on Natural Fiber Reinforced Polymer Composite and Its Applications

Properties of kenaf filled polypropylene composites containing ammonium polyphosphate as flame retardant

This study is part of ongoing research on the preparation of electrically conductive and physically stable Polyaniline/Sago starch (PANI/Sago) blend films using a simple one-pot synthesis method. The synthesis of PANI in the presence of Sago to prepare the PANI/Sago blend was done via in situ polymerization using ultrasound irradiation. For in situ polymerization of PANI/Sago blends, ammonium persulfate (APS) was used as an oxidant while hydrochloric acid (HCl) acted as a dopant. The effect of sonication time (0.5–5 h) on the structural properties (1H NMR and FT-IR), electrical conductivity (E.C), optical properties (UV-VIS), and the morphological (FE-SEM) and thermal stability (TGA) of the prepared PANI/Sago blends was studied. 1H NMR and FT-IR results revealed that the polymerization of PANI/Sago for more than 2 h leads to the disintegration/deformation of Sago starch due to excessive kinetic energy generated via the continuous collapsing of cavitation bubbles. In addition to the findings about Sago starch, FT-IR analysis also revealed the dominance of PANI property for the blend sonicated for 2 h as it contains a sharp and intense PANI peak at 1,500 cm−1, which represents the stretching vibration of benzenoid ring. 1H NMR and FT-IR results were found to be in compliance with E.C results, which showed the E.C of the blend sonicated for 2 h was highest. The UV-Vis results in combination with energy band values, thereby supporting the E.C results. The morphology of the prepared blends was found to be highly connected, which helps with good inter- and intra-chain electron transfers within the blends. The variation in sonication time seems to have very little impact on the thermal stability of the blends, as it was found that all blends were thermally stable up to 200°C, and only minor variation was observed beyond that.

/pdf/the-effect-of-sonication-time-on-the-properties-of-1beklyjgir.pdf

The Effect of Sonication Time on the Properties of Electrically Conductive PANI/Sago Starch Blend Prepared by the One-Pot Synthesis Method

The effects of chlorinated polyethylene (CPE) and acrylic impact modifier (AIM) on the thermal degradation of poly(vinyl chloride) (PVC) compounds and composites were investigated. The amounts of AIM and CPE used were fixed at 9 parts per hundred parts of resin (phr), while oil palm empty fruit bunch (OPEFB) fiber content was increased from 0 to 40 phr. To produce composites, the PVC formulations were dry-blended by using a laboratory blender before being milled into sheets on a two-roll mill at 165°C. The milled sheets were then hot-pressed at 180°C. The thermal degradation of the specimens was evaluated by using thermogravimetry in a nitrogen environment. Thermal stability of the PVC/CPE compounds and PVC/CPE/OPEFB composites was improved by the addition of CPE. The CPE retarded the dehydrochlorination of PVC. However, the stabilization effect was reduced by the incorporation of OPEFB at levels of 30 and 40 phr. The presence of AIM accelerated the dehydrochlorination of PVC/AIM compounds and PVC/AIM/OPEFB composites.

Comparative study of the effects of chlorinated polyethylene and acrylic impact modifier on the thermal degradation of poly(vinyl chloride) compounds and poly(vinyl chloride)/(oil palm empty fruit bunch) composites

The effects of formulation design on the tensile, morphological, and biodegradability properties of hybrid cellulose nanowhiskers/montmorillonite (CNW/MMT) reinforced polylactic acid (PLA) nanocomposites were investigated in this chapter. The CNWs were obtained from microcrystalline cellulose (MCC) using chemical swelling with N,N-dimethylacetamide containing 0.5% lithium chloride. Based on the tensile properties of PLA/MMT nanocomposites, 5 phr (parts per hundred parts of resin) MMT was selected as optimum content (P/MT5/CW0). The PLA/MMT/CNW hybrid nanocomposites were prepared using two different sets of formulations by solution casting method. The hybrid nanocomposites were produced by incorporation of different content of CNW (1, 3, 5, 7, and 9 phr) into P/MT5/CW0 nanocomposite and partial replacement of MMT with CNW at total filler content of 5 phr. The highest tensile strength for the PLA/MMT/CNW hybrid nanocomposites was obtained at 1 phr CNW for both sets of formulations. Interestingly, the ductility of the hybrid nanocomposites increased remarkably from approximately 10 to 90 and 79% by incorporation of 1 phr CNW into P/MT5/CW0 nanocomposite and partial replacement of 1 phr MMT with CNW, respectively. Furthermore, the biodegradability of PLA/MMT/CNW hybrid nanocomposites improved compared to neat PLA and optimum formulation of PLA/MMT nanocomposites.

Azman Hassan

Papers

Properties of kenaf filled polypropylene composites containing ammonium polyphosphate as flame retardant

The Effect of Sonication Time on the Properties of Electrically Conductive PANI/Sago Starch Blend Prepared by the One-Pot Synthesis Method

Comparative study of the effects of chlorinated polyethylene and acrylic impact modifier on the thermal degradation of poly(vinyl chloride) compounds and poly(vinyl chloride)/(oil palm empty fruit bunch) composites

Hybrid montmorillonite/cellulose nanowhiskers reinforced polylactic acid nanocomposites: A comparative study based on formulation design

Synthetic wollastonite nanofiber for polybutylene terephthalate nanocomposite: Mechanical, thermal, tribological and flammability properties