Polyacrylonitrile, uses

Polyacrylonitrile, uses of, 242 Polyalkylation, l- riedel-Crafts reaction and, 556 Polyamide, 818... 

The same authors (5) showed also in another work that the presence of larger amounts of lignin in bisulfite pulps may have a favourable effect on grafting polyacrylonitrile using the cellulose xanthate-hydrogen peroxide redox system to initiate the copolymerization reaction. The plots of the total conversion as well as of polymer loading show a minimum centered around approximately 15% of lignin. 

Table 2.2.7. Calculated heats of formation and entropies for acrylonitrile and polyacrylonitrile using MOPAC-7 [22],...

Definition Copolymer formed by the controlled hydrolysis of polyacrylonitrile Uses Film-former in cosmetics emulsifier, thickener, gellant, film-former for pharmaceuticals... 

Reference methods for criteria (19) and hazardous (20) poUutants estabHshed by the US EPA include sulfur dioxide [7446-09-5] by the West-Gaeke method carbon monoxide [630-08-0] by nondispersive infrared analysis ozone [10028-15-6] and nitrogen dioxide [10102-44-0] by chemiluminescence (qv) and hydrocarbons by gas chromatography coupled with flame-ionization detection. Gas chromatography coupled with a suitable detector can also be used to measure ambient concentrations of vinyl chloride monomer [75-01-4], halogenated hydrocarbons and aromatics, and polyacrylonitrile [25014-41-9] (21-22) (see Chromatography Trace and residue analysis). 

The membrane material strongly influences the effect of US energy on filtration. Water permeation through a polyacrylonitrile (PAN) membrane from a dextran [96], that of NaCI through a nylon membrane coated with amphiphiles [97], the transport of organic compounds aoross a polymer membrane suspension, and that of hydrocortizone and benzoio aoid through a cellulose membrane and poly-dimethylsiloxane membrane, respeotively [98], illustrate the influence of the membrane material on the type of particles it can retain optimally. 

The existence of carbon liber (CFs) came into being in 1879 when Thomas Edison recorded the use of carbon fiber as a filament element in electric lamp. Fibers were first prepared from rayon fibers by the US Union Carbide Corporation and the US Air Force Materials Laboratory in 1959 [41 ]. In 1960, it was realized that carbon fiber is very usefirl as reinforcement material in many applications. Since then a great deal of improvement has been made in the process and product through research work carried out in USA, Japan and UK. In 1960s, High strength Polyacrylonitrile (PAN) based carbon fiber was first produced in Japan and UK and pitch based carbon fiber in Japan and USA. 

In all the preceding polymerization methods we have seen how to utilize the double bond in an unsaturated organic compoimd to link many molecules together into a polymeric chain. Also, in all of these processes the polymer was produced starting from a single monomer. In contrast in this section we will look at polymers that are prepared from the reaction of two difunctional monomers with each other. In all the polymerization reactions that we have seen so far there was no side-product formation. For example, ethylene was converted into polyethylene acrylonitrile was converted into polyacrylonitrile and so on. During this conversion the entire stmc-tural unit of the monomer was incorporated into the polymer without any side-product formation. However, in the preparation of condensation polymers a small molecule (such as water or methanol) is eliminated as the side-product. Another important difference is that condensation polymerization is usually a step-growth polymerization. This means that the polymerization proceeds in a series of steps. To make this point clear let us recall the polymerization of ethylene by the free-radical method. In the free-radical process the polymerization of various chains are initiated by the... 

Donnet JB, Bansal RC (1984) Carbon Fiber. Marcel Dekker, New York, NY, USA Saufi SM, Ismail AF (2002) Development and characterization of polyacrylonitrile (PAN) based carbon hollow fiber membrane. Songkianakarin J Sci Technol 24 (SuppI) 843-854 Schindler E, Maier F (1990) Manufacture of porous carbon membranes. US Patent 4,919,860 Yoneyama H, Nishihara Y (1990) Porous hollow carbon fiber film and method of manufacturing the same. EP Patent 0,394,449... 

Soffer A, Koiesh J, Sagee S (1987) Separation device. US patent 4919860 Ismail AF, Saufi SM (2003) Development and characterization of PAN-based carbon hollow fiber membrane foroxygen/nitrogen separation, Regional Symposium and Workshop Membrane Science and Technology , 13-17 January 2003, Songkhla, Thailand Dalton S, Heatley F, Budd PM (1999) Thermal stabilization of polyacrylonitrile fibers. Polymer 40 (20) 5531-5543... 

The first commercial SAP was produced through alkaline hydrolysis of starch-graft-polyacrylonitrile, and was developed in the 1970s at the Northern Regional Research Laboratory of the US Department of Agriculture. Expense and inherent structural disadvantages of this product, such as a lack of sufficient gel strength, are seen as the major factors in its early market defeat. 

More than 250 million cars are registered in the US (2007), and approximately 20 million cars are scraped every year. Hence, we have around 60,000 tons of seat covers annually. The fibers used for these covers are polyester (more than 55%), polyamide and mixtures of staple fibers (24%), and also polyacrylonitrile fibers (14%). 

The corresponding values for nonswollen networks were calculated according to Eq. 94. The total fractions of the free volume are equal to 0.13 for PU and 0.46 for semi-IPN. Unfortunately, the restricted data do not allow us to make general conclusions about the contribution of free volume changes to the viscoelastic properties of IPNs. Experimentally, free volume in PU/polyacrylonitrile IPNs has been studied by using the method of positron annihilation [128]. 

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