Magnetic Properties of Irradiated Nickel Ferrite Thermoplastic Natural Rubber Nanocomposite

2014 ◽  
Vol 879 ◽  
pp. 206-212 ◽  
Author(s):  
Sivanesan Appadu ◽  
Sahrim Hj. Ahmad ◽  
Chantara Thevy Ratnam ◽  
Meor Yahaya Razali ◽  
Moayad Husein Flaifel ◽  
...  

The effect of electron beam (EB) irradiation at different doses on the magnetic, microstructure, morphological and thermal properties of NiFe2O4/Thermoplastic Natural Rubber (TPNR) nanocomposite was investigated. The NiFe2O4/TPNR nanocomposite samples were prepared by using a Haake mixer in weight ratio of 12:88. The TPNR matrix consists of natural rubber (NR), liquid natural rubber (LNR) and high density polyethylene (HDPE) in weight ratio of 20:10:70. The samples were irradiated using a 2 MeV EB machine in doses from 0 - 200 kGy. Magnetic properties studied by using the vibrating sample magnetometer (VSM) at room temperature showed that the values of saturation magnetization (MS), remanence magnetization (MR) and the coercivity (HC) value increased with increasing doses of irradiation. The increase in MSand MRvalues is attributed to the increase in concentration of Fe3+ions at octahedral B-site and decrease of concentration at the tetrahedral A-site in the NiFe2O4cubic structure. X-ray diffraction (XRD) analysis of the samples showed that peak intensities decreased and the width of the peaks increased with increasing doses of irradiation. Scanning electron microscope (SEM) image of the nanocomposite cross section showed the presence of defects which is more visible with increasing doses of irradiation. In the case of thermal properties, differential scanning calorimetry (DSC) analysis showed that the crystallization temperature (Tc) and the degree of crystallinity (Xc) of the nanocomposite samples decreased with increasing doses of irradiation due to crosslinking of polymeric chains which hinders the growth of crystals.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Emi Govorčin Bajsić ◽  
Vesna Rek ◽  
Ivana Ćosić

The effect of the addition of talc on the morphology and thermal properties of blends of thermoplastic polyurethane (TPU) and polypropylene (PP) was investigated. The blends of TPU and PP are incompatible because of large differences in polarities between the nonpolar crystalline PP and polar TPU and high interfacial tensions. The interaction between TPU and PP can be improved by using talc as reinforcing filler. The morphology was observed by means of scanning electron microscopy (SEM). The thermal properties of the neat polymers and unfilled and talc filled TPU/PP blends were studied by using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The addition of talc in TPU/PP blends improved miscibility in all investigated TPU/T/PP blends. The DSC results for talc filled TPU/PP blends show that the degree of crystallinity increased, which is due to the nucleating effect induced by talc particles. The reason for the increased storage modulus of blends with the incorporation of talc is due to the improved interface between polymers and filler. According to TGA results, the addition of talc enhanced thermal stability. The homogeneity of the talc filled TPU/PP blends is better than unfilled TPU/PP blends.


2013 ◽  
Vol 812 ◽  
pp. 125-130 ◽  
Author(s):  
Siti Norasmah Surip ◽  
Z.Y. Zhang ◽  
H.N. Dhakal ◽  
N.N. Bonnia ◽  
S. H. Ahmad

The effect of preparation technique on the crystallisation behavior and thermal properties of TPNR filled nanoclay nanocomposites was investigated. The nanocomposites were prepared via melt blending method using internal mixer (Haake 600P). Two types of nanocomposites preparation technique were employed which is method A and B. In method A, the nanoclay was pre-mixed with liquid natural rubber (LNR) before it was charged into the other materials. For method B, the nanoclay was directly charged into the molten TPNR matrix. The result shows, preparation methods were significantly affect the crystallinity and thermal properties of TPNR nanocomposites. DSC thermogram revealed that nanocomposites crystallinity was increased when prepared by method A but decreased with method B. An increment in polypropylene crystallinity was attributed by the nanoclay which is believed to be as a nucleating agent. DMA thermogram suggested that the preparation method has affected the storage modulus and tan δ but not the glass transition temperature (tg).


2021 ◽  
Vol 285 ◽  
pp. 07034
Author(s):  
Yulia Tertyshnaya ◽  
Maksim Zakharov ◽  
Alina Ivanitskikh ◽  
Anatoliy Popov

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.


2013 ◽  
Vol 795 ◽  
pp. 433-437 ◽  
Author(s):  
S.T. Sam ◽  
N.Z. Noriman ◽  
S. Ragunathan ◽  
O.H. Lin ◽  
H. Ismail

Soya spent powder as an inexpensive and renewable source has been used as a filler for linear-low density polyethylene (LLDPE) in this study. Linear-low density polyethylene (LLDPE)/soya spent powder composites were prepared by using Haake internal mixer. The mixing time was 10 minutes at 150°C with rotor speed 50 rpm. Epoxidised natural rubber (ENR 50) has been used as a compatibilizer in the present study. The thermal properties of the LLDPE/soya spent powder composites with and without ENR were studied with a differential scanning calorimetry (DSC). The crystallinity of the LLDPE/soya spent powder composites decreased with increasing soya spent powder content. However, the addition of ENR 50 as a compatibilizer increased the crystallinity of the LLDPE/soya spent powder composites.


2012 ◽  
Vol 626 ◽  
pp. 229-232 ◽  
Author(s):  
Ekwipoo Kalkornsurapranee ◽  
Charoen Nakason ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann

Thermoplastic natural rubber based on epoxidized natural rubber (ENR) and thermoplastic polyurethane (TPU) blend was prepared via dynamic vulcanization process. The main objective is to improve thermal properties of the blends. Two types of antioxidant: phenolic antioxidant (Wingstay®L) and N-(1,3-dimethzlbutyl)-N-Phenyl-p-phenylenediamine (6PPD) were used to improve oxidative degradation of the blends. It was found that thermal properties in term of thermal elastic properties and thermal stability can be improved by adding the antioxidants and 6PPD gave the blend with the highest thermal properties. These were measured based on temperature scanning stress relaxation (TSSR) technique. Incorporation of ENR into the TPU caused reduction of the hardness, improved thermal properties, elasticity and oil resistance compared to the neat TPU. These results indicated that the novel high performance TPNRs with high elasticity can be prepared.


2004 ◽  
Vol 58 (10) ◽  
pp. 444-449
Author(s):  
Branka Tanasijevic ◽  
Salem Elkhaseh ◽  
Marija Nikolic ◽  
Jasna Djonlagic

A series of thermoplastic poly(ester-olefin) elastomers, based on poly(ethylene-stat-butylene), HO-PEB-OH, as the soft segment and poly (butylene terephthalate), PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene) segments into the copolyester backbone was accomplished by the polycondensation of ?, ?-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol) with 1,4-butanediol (BD) and dimethyl terephthalate (DMT) in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu)4), and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD), as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu)4) for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylene)s were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefin)s were investigated by differential scanning calorimetry (DSC). The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA). The rheological properties of poly(ester-olefin)s were investigated by dynamic mechanical spectroscopy in the melt and solid state.


2020 ◽  
Vol 10 (24) ◽  
pp. 8863
Author(s):  
Klementina Pušnik Črešnar ◽  
Lidija Fras Zemljič ◽  
Lidija Slemenik Perše ◽  
Marko Bek

Novel wood fiber (WF)-polypropylene composites were developed using the extrusion process with a twin-screw extruder. The influence of different mass addition of WF to unrecycled polypropylene (PP) and recycled PP (R-PP) on the chemical, thermal and rheological properties of the processed WF-PP and WF-R-PP composites was investigated. For this purpose, the chemical surface structure of the composites was followed with ATR-FTIR (attenuated total reflection Fourier transform infra red spectroscopy), while the thermal properties of the WF-PP composites were investigated with differential scanning calorimetry (DSC). Furthermore, the crystalline structure of the composites was determined by X-ray diffraction (XRD) analysis. Finally, the rheology of the materials was also studied. It was observed that a stronger particle formation at high additional concentrations was observed in the case of recycled PP material. The addition of WF over 20% by weight increased the crystallinity as a result of the incorporation and reorganization of the WF and also their reinforcing effect. The addition of WF to pure PP had an influence on the crystallization process, which due to the new β phase and γ phase PP formation showed an increased degree of crystallinity of the composites and led to a polymorphic structure of the composites WF-PP. From the rheological test, we can conclude that the addition of WF changed the rheological behavior of the material, as WF hindered the movement of the polymeric material. At lower concentrations, the change was less pronounced, although we observed more drastic changes in the material behavior at concentrations high enough that WF could form a 3D network (percolation point about 20%).


2014 ◽  
Vol 616 ◽  
pp. 325-332
Author(s):  
Luboš Bĕhálek ◽  
Martin Seidl ◽  
Jozef Dobránsky

This paper deals with the evaluation of crystalline structure and thermal properties of injection molded parts based on polylactic acid (PLA) matrix reinforced by banana and hemp natural fibres (NF). Using differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD) methods were evaluated thermal properties and crystalline structure of PLA/NF composites, depending on the amount of natural fibres within the weight ratio of 10% up to 30%. We observed that hemp and banana fibres work like natural nucleating agents and thus subsequently improve the material properties of PLA. We also observed process of melt (primary) and cold (secondary) crystallization of PLA/NF composites depending on cooling rate.


2020 ◽  
Vol 10 (7) ◽  
pp. 2636
Author(s):  
Hom Nath Dhakal ◽  
Sikiru Oluwarotimi Ismail ◽  
Johnny Beaugrand ◽  
Zhongyi Zhang ◽  
Jurgita Zekonyte

The quest for sustainable, low-cost and environmental friendly engineering materials has increased the application of natural fiber-reinforced polymer (FRP) composite. This paper experimentally investigates the effects of variable mean hemp fiber (HF) aspect ratios (ARs) of 00 (neat), aspect ratios AR_19, AR_26, AR_30 and AR_38 on nano-mechanical (hardness, modulus, elasticity and plasticity), surface and thermal properties of hemp fiber/polycaprolactone (HF/PCL) biocomposites. These biocomposites were characterized by nanoindentation, contact angle, surface energy, thermogravimetric analysis (TGA), thermal conductivity and differential scanning calorimetry (DSC) techniques. After nanoindentation and thermal conductivity tests, the results obtained evidently show that the HF/PCL sample with aspect ratio (AR_26) recorded optimal values. These values include maximum hardness of approximately 0.107 GPa, elastic modulus of 1.094 GPa, and plastic and elastic works of 1.580 and 1.210 nJ, respectively as well as maximum thermal conductivity of 0.2957 W/mK, when compared with other samples. Similarly, the optimal sample exhibits highest main degradable temperature and degree of crystallinity of 432 ℃ and 60.6%, respectively. Further results obtained for the total surface energies and contact angles of these samples with glycerol and distilled water are significant for their materials selection, design, manufacturing and various applications.


Food Research ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 873-886
Author(s):  
M.A. Hashim ◽  
F. Yahya ◽  
Y. Hamzah ◽  
Wan Aida W.M. ◽  
K.H. Khalid

The citral compound that contributes to the strong-lemony odour of lemongrass has high volatility and low physicochemical stability. To overcome the problems, the inclusion complex of the encapsulation technique was applied with rice starch as a coating material to improve the stability and protect against any unfavourable reaction. Therefore, this study was conducted to determine the structural characterization, citral retention and thermal properties of native rice starch, gelatinised rice starch, inclusion complex of rice starch–citral compound, and inclusion complex of rice starch–lemongrass extract. Lemongrass extract and standard citral compound were homogenised into rice starch dispersion at 80oC for 15 mins and freeze-dried at −50.0±2.0oC. The formation of the inclusion complex powder was determined using different analyses including morphological structure using the scanning electron microscope, crystallinity structure was determined with X-ray diffractometer, identification and quantification of citral compound using HS-SPME-GC-FID and the thermal properties of inclusion complex analyzed using differential scanning calorimetry. The microstructure of both inclusion complex of rice starch-lemongrass extract and rice starch-citral compound exhibited a laminated multiangular shape with crumble formation together with the characteristics of V-type pattern of crystalline complexes. The low degree of crystallinity of the inclusion complex of rice starch–lemongrass extract obtained high in citral entrapment (29.34±3.13%) with the highest concentration of citral retention (7.33±0.78 ppm). Both inclusion complex of rice starch-citral compound and rice starch-lemongrass extract displayed an endothermic peak at 138oC, which is attributed to an inclusion complex occurrence with significant difference (p<0.05) of enthalpy of 0.44±0.05 J/g and 1.61±0.70 J/g, respectively. These findings showed that rice starch was effective in complexing with aroma compounds in improving the stability and protecting the citral compound of lemongrass extract from any unwanted changes. This inclusion complex should be regarded as an important strategy in designing a novel model of citral compound of lemongrass for food flavouring application.ha


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