Dynamic mechanical relaxations of electrospun poly(acrylonitrile-co-methyl acrylate) nanofibrous yarn

2016 ◽  
Vol 87 (18) ◽  
pp. 2193-2203 ◽  
Author(s):  
Seyed Abdolkarim Hosseini ◽  
Ning Pan ◽  
Frank Ko
Keyword(s):  
Methyl Acrylate ◽  
Phase Structure ◽  
Molecular Orientation ◽  
Polymorphic Transition ◽  
Solution Concentration ◽  
Dynamic Mechanical Properties ◽  
Two Phase ◽  
Dynamic Mechanical ◽  
Nanofibrous Yarn ◽  
Poly Acrylonitrile

The phase structure and dynamic mechanical properties of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) nanofibers collected in the form of twisted yarn via the two-nozzle conjugated electrospinning method were investigated to study the effects of solution concentration and take-up velocity on the relaxation behavior of nanofibers yarn. The wide-angle X-ray diffraction analyses of P(AN-co-MA) nanofibers show a two-phase structure of nanofibers consisting of crystalline and amorphous phases and polymorphic transition from hexagonal to orthorhombic. Heating P(AN-co-MA) nanofibers at over the glass transition temperature led to an increased degree of both crystallinity and crystallite size with no polymorphic change. Three transitions (tan δ peaks) were observed in nanofibrous yarn prepared at different spinning dope concentrations and take-up speeds, except for the specimen prepared at a concentration of 14 wt% and collecting speed of 8 cm/min, wherein no α transition was observed due to improved molecular orientation. The temperature dependence of the dynamic Young’s modulus of nanofibrous yarn at different spinning dope concentrations was mainly affected by the diameter of the nanofiber as the morphological property and molecular orientation. Take-up speed was found to affect the γ and α transitions more than the β transition. Moreover, the maximum storage modulus was obtained at a take-up speed of 8 cm/min at all over recorded temperatures.

Thermoplastic Elastomeric Blends of Nylon-6/Acrylate Rubber: Influence of Interaction on Mechanical and Dynamic Mechanical Thermal Properties

1997 ◽  
Vol 70 (5) ◽  
pp. 798-814 ◽  
Author(s):  
Abhijit Jha ◽  
Anil K. Bhowmick
Keyword(s):  
Morphological Structure ◽  
Nylon 6 ◽  
Spectroscopic Studies ◽  
Dynamic Mechanical Properties ◽  
Epoxy Acid ◽  
Substantial Improvement ◽  
Melt Mixing ◽  
Dynamic Vulcanization ◽  
Two Phase ◽  
Dynamic Mechanical

Abstract Nylon-6 and acrylate rubber (ACM) were melt blended in a Brabender Plasticorder at 220 °C and 40 rpm rotor speed. The reactive nature of the blend is reflected in the mixing torque behavior of the blends at different compositions. The solubility characteristics of the blends in formic acid solution gives an approximate idea of the amount of nylon-6 grafted onto ACM and vice-versa. A reaction mechanism is proposed based on the well known epoxy—amine and epoxy—acid reactions and is confirmed by infrared spectroscopic studies of the blends. The influence of interaction between the two polymers on the mechanical and the dynamic mechanical properties of the blends is analyzed in detail, and the results are interpreted on the basis of the formation of nylon—ACM graft copolymer at the interfaces. The dynamic mechanical thermal analysis (DMTA) reveals a two phase morphological structure, indicating incompatibility of the blend components. The grafting reaction results in dramatic increase in both the storage modulus and the Young's modulus of blends. The presence of grafted rubber chains is reflected in the secondary transition of the rubber loss peak at higher temperature. Also, a substantial improvement in the damping properties of the blends in the service temperature range (i.e., 25 to 175 °C) is revealed from the DMTA results. The dynamic vulcanization of the ACM phase during melt mixing improves the elongation at break values of the blends.

Dynamic Mechanical Properties of PMMA/Organoclay Nanocomposite: Experiments and Modeling

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Rodrigue Matadi Boumbimba ◽  
Said Ahzi ◽  
Nadia Bahlouli ◽  
David Ruch ◽  
José Gracio
Keyword(s):  
Mechanical Properties ◽  
Amorphous Polymers ◽  
Dynamic Mechanical Properties ◽  
Unified Model ◽  
Strain Rates ◽  
Transition Temperatures ◽  
Two Phase ◽  
Stiffness Modulus ◽  
Dynamic Mechanical ◽  
Wide Range

Similarly to unfilled polymers, the dynamic mechanical properties of polymer/organoclay nanocomposites are sensitive to frequency and temperature, as well as to clay concentration. Richeton et al. (2005, “A Unified Model for Stiffness Modulus of Amorphous Polymers Across Transition Temperatures and Strain Rates,” Polymer, 46, pp. 8194–8201) has recently proposed a statistical model to describe the storage modulus variation of glassy polymers over a wide range of temperature and frequency. In the present work, we propose to extend this approach for the prediction of the stiffness of polymer composites by using two-phase composite homogenization methods. The phenomenological law developed by Takayanagi et al., 1966, J. Polym. Sci., 15, pp. 263–281 and the classical bounds proposed by Voigt, 1928, Wied. Ann., 33, pp. 573–587 and Reuss and Angew, 1929, Math. Mech., 29, pp. 9–49 models are used to compute the effective instantaneous moduli, which is then implemented in the Richeton model (Richeton et al., 2005, “A Unified Model for Stiffness Modulus of Amorphous Polymers Across Transition Temperatures and Strain Rates,” Polymer, 46, pp. 8194–8201). This adapted formulation has been successfully validated for PMMA/cloisites 20A and 30B nanocomposites. Indeed, good agreement has been obtained between the dynamic mechanical analysis data and the model predictions of poly(methyl-methacrylate)/organoclay nanocomposites.

Fabrication and Stabilization of Poly(Acrylonitrile-сo-Methyl Acrylate) Nanofibers

2018 ◽  
Vol 775 ◽  
pp. 43-49
Author(s):  
Krittiya Singcharoen ◽  
Wansika Sirimongkol ◽  
Soontree Khuntong ◽  
Ratthapol Rangkupan
Keyword(s):  
Methyl Acrylate ◽  
Solution Concentration ◽  
Processing Parameters ◽  
Solution Flow Rate ◽  
Fiber Morphology ◽  
Scanning Calorimetry ◽  
Stabilization Time ◽  
Sem Images ◽  
Solution Flow ◽  
Poly Acrylonitrile

In present study, poly (acrylonitrile-co-methyl acrylate) nanofibers were fabricated via electrospinning method and stabilized at elevated temperature in air. Electrospinning processing parameters i.e. solution concentration, solution flow rate and applied voltage were optimized. Fiber morphology and polydispersity index of fiber size was assessed from scanning electron microscope (SEM) images. Selected nanofiber was then used to study effect of stabilization time and stabilization temperature on fiber morphology, change in chemical structure and aromatization index (AI) using Fourier transform infrared spectroscopy and differential scanning calorimetry. SEM images showed drastic morphological change of stabilized fibers compared to the as spun precursor. AI value increased as stabilization time and temperature increased and reaching maximum value of 98%. This indicated high cyclization of the aromatic ring in fiber structure. Current finding is critical for carbonization process and preparation of carbon nanofibers from PAN copolymer in the future.

Dynamic Mechanical Properties and Phase Structure of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2013 ◽  
Vol 457-458 ◽  
pp. 293-296
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Polymer Matrix ◽  
Phase Structure ◽  
In Situ Polymerization ◽  
Conformational Transitions ◽  
Dynamic Mechanical Properties ◽  
Strong Interactions ◽  
Dynamic Mechanical

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The dynamic mechanical properties and phase structure of PE/MMT nanocomposites at different MMT concentrations (from 0.1 to 1.2 wt %) were studied. The storage modulus of PE/MMT nanocomposites is higher than that of the polymer matrix. And the motions of molecular relaxations and conformational transitions both in non-crystalline and crystalline phases are confined by the strong interactions between polymer and MMT. Otherwise, the spherulite size gradually decreases with the increasing content of MMT.

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