Center for Advanced Scientific Research and Rural Technology

Kollam, India

Center for Advanced Scientific Research and Rural Technology

Kollam, India

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Jayasree T.K.,National Institute of Technology Calicut | Jayasree T.K.,Center for Advanced Scientific Research and Rural Technology | Jayasree T.K.,Sree Ayappa College | Predeep P.,National Institute of Technology Calicut | Predeep P.,Center for Advanced Scientific Research and Rural Technology
Journal of Thermal Analysis and Calorimetry | Year: 2012

The thermal and crystallization behavior of the blends are studied by differential scanning calorimetry and XRD. The presence of the amorphous component in the blend is found to influence the non-isothermal crystallization of HDPE. The addition of small quantities of SBR resulted in an increase in the rate of crystallization whereas nucleation is delayed. As compared to HDPE, larger crystallite size, a narrower size distribution, were observed in low SBR (~up to 30 wt%) content blends. The half time of crystallization also found to reduce as the SBR content in the blend increased. However, a lower degree of crystallinity was observed in these blends. The results thus show that incorporation of SBR in HDPE, while accelerating the rate of crystallization, lower the degree of crystallization. The reduction in the overall crystallization rate at high-SBR content is attributed to a decrease in the growth rate in the later stages of crystallization. It is observed that in dynamically cross-linked blends, the presence of crosslinked SBR that can acts as heterogeneous nuclei facilitated the nucleation of HDPE. However, the crystal growth may be impeded. As a result the overall crystallinity of the crosslinked blends found to decrease. From XRD profiles it had seen that addition of SBR and dynamic crosslinking does not exert an effect on the crystalline structure of HDPE. The dynamic vulcanization of SBR/HDPE blends enhanced the process of crystallization of HDPE phase. These conclusions are supported by the thermal characterization (DSC) results also. © 2012 Akadémiai Kiadó, Budapest, Hungary.


Mathew A.M.,National Institute of Technology Calicut | Mathew A.M.,Center for Advanced Scientific Research and Rural Technology | Predeep P.,Center for Advanced Scientific Research and Rural Technology
Polymer Composites | Year: 2013

Plasma polymerization is an excellent and inexpensive tool for growing uniform, ultrathin amorphous and pinhole-free polymer layer on different substrates and also for forming polymer composites. This work reports the synthesis and characterization of Styrene Butadiene Co-polymer (SBR) based conducting polymer composites by plasma polymerization using a home built DC plasma polymerization setup. Optical, morphological, and cyclic voltammetric studies reveal an effective formation of composite structure containing SBR and Polyaniline (Pani). The chemical structure of the composite film is studied using FTIR spectroscopy. The films prepared are highly cross-linked, amorphous in nature and have band gap of 2.8 eV. Moreover, it is found that I2 doping of the composites enhances their conductivity to a desirable value. The band gap energy of the composite film decreases from 2.8 eV to 2 eV by iodine doping. SEM and AFM images show the uniformity in film morphology. The refractive index of the film is found to be 1.87 and dielectric constant is 3.4 at a wavelength 620 nm in the visible region. © 2013 Society of Plastics Engineers.


Sreelatha K.,Sree Narayana College | Sreelatha K.,Center for Advanced Scientific Research and Rural Technology | Predeep P.,National Institute of Technology Calicut
Journal of Plastic Film and Sheeting | Year: 2013

An attempt has been made to develop intrinsically conducting nylon 6 films by iodine doping and investigate the doped material in terms of electrical, structural and optical characteristics. The electrical conduction increases with increasing iodine content as iodine forms charge transfer complexes with the polymer matrix and conductivity of the order of 10-3 Scm-1 is obtained with films that contained 200 wt% iodine. The extent of crystallinity reduced from 53% for pristine nylon 6 films to 47% for iodine doped nylon 6 films (200 wt% iodine). The band gap reduced from 5 eV to 2.40 eV for iodine doped nylon 6 films (200 wt% iodine). The melting point of the matrix polymer reduced from 220 C to approximately 200 C for iodine doped nylon 6 films (200 wt% iodine). © The Author(s) 2012 Reprints and permissions:sagepub.co.uk/ journalsPermissions.nav.


Faseena N.M.,National Institute of Technology Calicut | Faseena N.M.,Center for Advanced Scientific Research and Rural Technology | Santhamma G.,National Institute of Technology Calicut | Santhamma G.,Center for Advanced Scientific Research and Rural Technology | And 4 more authors.
Journal of Elastomers and Plastics | Year: 2014

Conducting plastics emerge as a new area of providing a cost effective and unique alternative material for applications ranging from consumer electronics to optoelectronics, solar cells, lighting, memory and a host of new photonic applications. In this work, an attempt has been made to produce conducting elastomeric thin films pertinent to optoelectronic applications. A thermoplastic elastomer, styrene butadiene rubber, is doped with suitable dopants by chemical-doping method. The spectroscopic analysis reveals the formation of conjugated sequences, which is responsible for high intrinsic conductivity in polymeric materials. The polystyrene segment of the elastomer seems to affect the doping rate and the length of the conjugated sequences formed. In this study, the electrical conductivity is found to increase from 10-13 S cm-1 to 10-1 S cm-1 upon doping, and the conduction mechanisms involved are also proposed. © The Author(s) 2012.


Anisha M.M.,Center for Advanced Scientific Research and Rural Technology | Faseena N.M.,National Institute of Technology Calicut | Predeep P.,National Institute of Technology Calicut
Plastics, Rubber and Composites | Year: 2013

Homogeneous conducting polymer composite films with improved electrical properties are synthesised by electrochemical polymerisation of aniline on natural rubber. The electrochemical polymerisation is carried out by potentiostatic method using an aqueous solution of 0?1M aniline and 1M sulphuric acid as electrolyte in a single compartment electrochemical cell with steel electrode for collecting the polymer composite. The redox behaviour and stability of the film are studied by cyclic voltammetry. The morphological and spectroscopic analysis revealed an effective formation of the composite. The interfacial properties and ac conductivity of the deposited films are studied by impedance spectroscopy. © Institute of Materials, Minerals and Mining 2013.


Predeep P.,National Institute of Technology Calicut | Devasia D.,National Institute of Technology Calicut | Aneesh J.,National Institute of Technology Calicut | Faseena N.M.,Center for Advanced Scientific Research and Rural Technology
Microelectronic Engineering | Year: 2013

Memory devices based on C60 fullerene molecules and a polydiene, cis 1,4 polyisoprene (natural rubber) are described and their current bistability and switching characteristics during write-read-erase cycles are discussed. It is found that natural rubber nanocomposite with a fullerene content even as low as 0.1% exhibit bistability and switching behavior. Multiple tunneling and coulomb blockade effect along with dipolar carrier trapping are identified as the possible reasons for this current bistability. © 2013 Elsevier B.V. All rights reserved.

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