Polyacrylontrile synthesis, via atom transfer radical polymerization, is studied in various initiator concentrations, transitional metal catalyst and different concentrations of CuBr2. The variations of monomer conversion and the linearity of semi-logarithmic kinetic profile which is the evidence of living polymerization and constant radical concentration in the reaction medium, were revealed by gas chromatography technique (GC). Gel permeation chromatography (GPC) studies revealed that, the number average molecular weight increases linearly against monomer conversion, an indicative of living nature of the polymerization process. Additionally, the conversion, apparent rate constant and number average molecular weight increased with increased initiator concentration as well as the transitional metal complex concentration. However, addition of CuBr2 lowered conversion, kapp, and the number average molecular weight of POLYACRYLONITRILE. Molecular weight distribution of synthesized polymers broadened with increased initiator concentration and also transitional metal complex concentration. However, addition of CuBr2 has resulted in narrower molecular weight distribution POLYACRYLONITRILE. Moreover, all the samples experienced a drop in PDI value from nearly 2 to almost 1.1 as the reaction progressed.

Polystyrene/MCM–41 nanocomposites were synthesized by atom transfer radical polymerization (ATRP) at 110°C. Activators generated by electron transfer (AGET) and activators regenerated by electron transfer (ARGET), as two novel initiation techniques, for ATRP were used. Specific structure, surface area, particles size and their distribution and spongy and porous structure of the synthesized MCM–41 nanoparticles were evaluated using X–ray diffraction, nitrogen adsorption/desorption isotherm analysis, scanning and transmission electron microscopy images, respectively. The final monomer conversion was determined using gas chromatography. Number and weight average molecular weights (Mn and Mw) and polydispersity index (PDI) were also evaluated by gel permeation chromatography. According to the results, addition of 3 wt% MCM–41 nanoparticles into the polymerization media resulted in lowering conversion from 81 to 58% in the AGET ATRP system. Moreover, a reduction in the molecular weight of the products from 17116 to 12798 g/mol was also occurred, although, the polydispersity index increased from 1.24 to 1.58. The similar results were also obtained by ARGET ATRP system; lowering conversion from 69 to 43% and molecular weight from 14892 to 9297 g/mol, and an increase of PDI from 1.14 to 1.41. The improvement in thermal stability of the nanocomposites, as a result of higher MCM–41 nanoparticles loading, was confirmed by thermogravimetric analysis. In addition, according to the analytical results of differential scanning calorimetry, a decrease in glass transition temperature, due to the addition of 3 wt% of MCM–41 nanoparticles (from 100.1 to 91.5oC in AGET ATRP system and from 100.3 to 85.8oC in ARGET ATRP), was achieved.

Atom transfer radical polymerization (ATRP) provides a robust route to synthesize well-defined polymers with predetermined molecular weight and low polydispersity index. ATRP as a popular member of controlled radical polymerization (CRP) family provides some advantages over others among which the usage of different initiation techniques are unique features of ATRP. Although Reverse ATRP (RATRP) is an appropriate technique for overcoming oxidation problem, synthesis of block copolymer is impossible by this procedure. Despite RATRP, simultaneous reverse and normal initiation techniques (SR&NI) can be used to synthesize various block copolymers. Activators generated by electron transfer (AGET) and activators regenerated by electron transfer (ARGET) employ environmentally friendly reducing agents to activate a metal complex in its higher oxidation state. However, initiators for continuous activator regeneration (ICAR) initiation techniques use conventional radical initiator. Moreover, ARGET and ICAR ATRP are designed to decrease the metal catalyst concentration to ppm level, which is an important goal to industrial applications.

POLYACRYLONITRILE films are prepared from the polymer and dimethylformamide (DMF). The thermal treatment of the PAN film like the fibre is considered as an important step in the formation of the ladder polymer structure. The kinetics and thermodynamic studies of the PAN films indicated that the peak temperatures and the enthalpies of the reactions are lower than the PAN fibres. The properties of PAN films and fibres are studied on the basis of -CN groups dipole moment and coupling, and their energetics of the reaction with potassium permanganate catalyst and other additives like acetic acid are also determined.

The objective of this research work is to evaluate the surface roughness of POLYACRYLONITRILE (PAN) nanowebs. For this purpose the nanowebs have been prepared in different concentrations of PAN solution from 11 to 15% (by wt). Surface roughness of nanowebs was evaluated by entropy algorithm (ENT) as well as atomic force microscopy (AFM) and then the results of two methods have been compared. To evaluate surface roughness using AFM, four roughness parameters such as maximum height, ten point height, arithmetic mean of roughness (AMR), and root mean square were measured and AMR parameter was used as surface roughness. Based on the results obtained, the increase in concentration of PAN solution from 11 to 15% (by wt) would increase nanofiber diameter from 195 to 524 nm. The results obtained from two methods show that increasing the fiber diameters of nanowebs lead to the enhancement of surface roughness of samples. The correlation coefficient of surface roughness obtained from these two methods and nanofibers diameter is more than 0.90. Statistical analysis shows that there is a good agreement of surface roughness between the two methods.