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

The objective of this study is to investigate the effect of acid hydrolysis time on microcrystalline chitin (MCC) filled polylactic acid (PLA) biocomposites using solution casting method. MCC was produced from commercial chitin using controlled hydrolysis process at four different hydrolysis time; 15, 30, 45 and 60 min. The tensile and morphological properties of PLA/MCC biocomposites were investigated using tensile testing machine and atomic force microscopy (AFM), respectively. Tensile strength and Young’s modulus of PLA/MCC biocomposites increased gradually by increasing hydrolysis time. The biocomposites with longest hydrolysis time (60 min) showed the higher tensile strength, Young’s modulus and elongation at break values. AFM analysis showed homogeneous dispersion of MCC fillers with smaller particles size at longer hydrolysis time, resulted in smother surface morphology compared to biocomposites with shorter hydrolysis time.

Effect of acid hydrolysis time on tensile and morphological properties of microcrystalline chitin filled polylactic acid biocomposites

Blending is a combination of two or more polymer to produce a new polymer which has good mechanical properties at low cost Nylon 6 and ABS both have their specialty and weakness but on the other hand, with the combination of Nylon/ABS, it helps to patch both weaknesses For this study, high impact ABS was used to blend with PA 6 to improve the mechanical properties and to reduce the cost The main purpose of this study was to investigate the ratio of PA 6/ABS blends to produce a good combination of mechanical properties such as tensile, flexural and impact properties Besides, the study was also investigate the compatibility of PA 6/ABS and to examine the structure morphology of its blends For sample preparation, the pellets of PA 6 and ABS were extruded at the different composition using twin screw extruder and then being moulded using injection moulding machine In this study, the tests conducted were tensile test, flexural test, Izod impact test and morphology examination of PA 6/ABS blends With the increasing of ABS content in PA 6/ABS blend, the tensile strength, tensile modulus and elongation at break were decreased Besides, the flexural strength and flexural modulus of the blend were also decreased However, the addition of ABS increased the Izod impact strength of the blend The best ratio for the PA 6/ABS blends based on the mechanical properties is 60:40 PA 6/ABS

The mechanical properties of nylon 6 (pa6)/acrylonitrile-butadiene-styrene (ABS) blends

This study aims to investigate the effect of three factors, namely alumina trihydrate (ATH), montmorillonite (MMT) and irradiation dosage on the mechanical properties (tensile strength and elongation at break) of flame-retarded LDPE-EVA composites. In this study, full factorial design analysis was used to examine the effects of factors and their combination interactions on mechanical properties. ATH is the most significant factor in affecting the tensile strength of LDPE-EVA blends due to the poor compatibility effect between ATH particles and LDPE-EVA matrix. However, MMT is the least significant factor on tensile strength of LDPE-EVA composites. ATH was the most significant in affecting the elongation at break of LDPE-EVA blends. This is because the increasing of ATH amount in LDPE-EVA matrix could restrict the mobolity of polymer chains in LDPE-EVA matrix. However, the factor of irradiation dosage was found to be insignificant in affecting the elongation at break of LDPE-EVA blends.

Full Factorial Design Analysis on Mechanical Properties of Electron Beam Irradiated-Flame Retarded LDPE/EVA Composites

Sustainable flame retardant coating based graphene oxide and montmorillonite

This research aims to investigate the role of a new carbonizing agent (that is sepiolite) in the RPUF polymeric system's intumescent flame retardants (IFR) system, as well as the impact of sepiolite nanoclay on the morphology and flame resistance of the rigid PU foam polymeric system. This paper presents work on IFR formulation of ammonium polyphosphate (APP), sepiolite (SEP) and melamine (MEL) embedded in rigid polyurethane (foam RPUF). Rigid This research aims to investigate the role of sepiolite as a carbonizing agent in the RPUF polymeric system's intumescent flame retardants (IFR) system, as well as the impact of sepiolite nanoclay on the morphology and flame retardancy of the RPUF polymeric system. PU foam was prepared in a closed mould, and the amount of IFR constituents was varied in each foam formulation. The obtained foam was tested for its morphology and flame retardance. Scanning electron microscopy (SEM) revealed a fine, closed-cellular structure at 16phr IFR loading; increasing IFR content induced larger cell sizes with blowholes. Incorporating 16 and 20 phr IFR into RPUF increased the nanocomposites LOI values to 22.80 and 20.0 % respectively relative to pristine RPUF (18.00 %). The highest improvement in the LOI values for the nanocomposites was achieved at 16 phr IFR/RPUF compared to previous studies with 25 phr. The nanocomposites passed the UL-94 testing with a V-0 grade in comparison with neat RPUF that failed the test. These results affirm that IFRs of APP/SEP/MEL have changed the morphology and improved the flame resistance of RPUF nanocomposites. Therefore, we identify robust possibility that the RPUF nanocomposite produced can be useful as an insulation material. 

Azman Hassan

Papers

Effect of acid hydrolysis time on tensile and morphological properties of microcrystalline chitin filled polylactic acid biocomposites

The mechanical properties of nylon 6 (pa6)/acrylonitrile-butadiene-styrene (ABS) blends

Full Factorial Design Analysis on Mechanical Properties of Electron Beam Irradiated-Flame Retarded LDPE/EVA Composites

Sustainable flame retardant coating based graphene oxide and montmorillonite

Intumescent flame retardant based on sepiolite filled rigid polyurethane foam