Nylon pellet

Various on-line SFE-SFC applications for the analysis of polymer additives and oligomers have been reported, such as additives in PE [121] polymer additives and oligomers in PP nylon pellets and PEEK granules [15] and oligomers in PET films [103], PS [122] and PMMA [123], sometimes in quantitative fashion [15,103]. SFE-SFC has identified the cyclic trimer tris-(ethylene terephthalate) in commercially available PET film [103]. Also, SFE-SFC extraction and... 

Heating the monomer vapors to which Nylon pellets, fibers or films are exposed, is another method for direct grafting, although not much used. Ethylene oxide vapors at about 80° C have been successfully employed for graft copolymerization of the polyamide skeleton by that procedure (187,188). 

Solids Conveying of Nylon in Screw Extruders Consider a 1.991-in-diameter screw with 2-in lead, 1.375-in root diameter, and 0.2-in flight width, conveying nylon pellets with bulk density of 0.475 g/cm3 and a coefficient of friction of 0.25. Assuming no pressure rise, calculate the solids conveying rate (g/rev) at the following conditions (a) no friction between the screw and the solids (b) no friction... 

Paddle dryers have been successfully used in drying such polymers as VC resin, nylon pellets, and polypropylene (PP), as well as polyethylene. Operated in a closed-cycle mode they can recover organics from such solvent-laden products as polyethylene or PP and can reduce the air volume requirement to only 5%-10% of that used in direct dryers. 

Fig. 4.9 Two examples of microtomed sections viewed in the optical microscope are shown (A) a section of a nylon pellet, in polarized light, reveals a coarse spherulitic texture and (B) a section from a black, molded nylon part, in a bright field micrograph, shows the size and distribution of the carbon black filler.

PIAB have also restricted the use of Equation (7.2) to conveying lengths of 4-30 m, materials of bulk density in the range of 500-1800 kg/m and for particles sizes of less than 5 mm. This bulk density range covers cement, dry sand, flour, nylon pellets, salt and sugar, to name a few common materials (McGlinchey 2005 Powder and Bulk Dot Com 2006). 

Fig. 2 Analysis of Flow Rate Data for Conveying of Nylon Pellets...

Blow tank air ratio data for the nylon pellets is presented on Fig 5. From this the control capability of the blow tank appears to be very poor aiui would probably not be recommended for a commercial aj lication. The control problem, however, is only significant in the area below the pressure minimum point and it is suggested that this is due to the conveying characteristics of the material and not the control characteristics of the blow tank. Lines of constant blow tank air ratio have been added and it will be seen that quite reasonable control of material feed rate is possible in the dilute phase conveyit region of the conveying characteristics for these pellets. 

Polymer Production. Three processes are used to produce nylon-6,6. Two of these start with nylon-6,6 salt, a combination of adipic acid and hexamethylenediamine in water they are the batch or autoclave process and the continuous polymerisation process. The third, the soHd-phase polymerisation process, starts with low molecular weight pellets usually made via the autoclave process, and continues to build the molecular weight of the polymer in a heated inert gas, the temperature of which never reaches the melting point of the polymer. 

Rotomolding. Nylon-6, nylon-11, and nylon-12 can be used in rotomolding and are generally suppHed for these appHcations as a powder or with a small pellet si2e. The process involves tumbling the resin in a heated mold to form large, thin-walled mol dings. Nylon-11 and nylon-12 use mold temperatures of 230—280°C and nylon-6 is processed at over 300°C. An inert gas atmosphere is preferred to avoid oxidation. 

Noryl. Noryl engineering thermoplastics are polymer blends formed by melt-blending DMPPO and HIPS or other polymers such as nylon with proprietary stabilizers, flame retardants, impact modifiers, and other additives (69). Because the mbber characteristics that are required for optimum performance in DMPPO—polystyrene blends are not the same as for polystyrene alone, most of the HIPS that is used in DMPPO blends is designed specifically for this use (70). Noryl is produced as sheet and for vacuum forming, but by far the greatest use is in pellets for injection mol ding. 

Nylon resins are made by numerous methods (53) ranging from ester amidation (54) to the Schotten-Baumann synthesis (55). The most commonly used method for making nylon-6,6 and related resins is the heat-induced condensation of monomeric salt complexes (56). In this process, stoichiometric amounts of diacid and diamine react in water to form salts. Water is removed and further heating converts the carboxylate functions to amide linkages. Chain lengths are controlled by small amounts of monofunctional reagents. The molten finished nylon resin can be dkectly extmded to pellets. 

The PEEK resia is marketed as aeat or filled pellets for iajectioa mol ding, as powder for coatiags, or as preimpregaated fiber sheet and tapes. Apphcations iaclude parts that are exposed to high temperature, radiation, or aggressive chemical environments. Aerospace and military uses are prominent. At present, polyamideimide (PAl) resia and poly(arylene sulfides) are the main competitors for apphcations requiring service temperatures of 280°C. At lower temperatures, polyethersulfones, amorphous nylons, and polyetherimides (PEI) can be considered. 

Nylon powder. Pellets were dissolved in ethylene glycol under reflux. Then ppted as a white powder on addition of EtOH at room temperature. This was washed with EtOH and dried at 100° under vacuum. 

The Augusta facility produced plastics, including Amodel, a hard but moldable high-performance nylon. Amodel is manufactured by passing a solution of diamines and dicarboxylic acids through a series of reactors. The reaction is completed in an extruder, and the material is then formed and cooled into solid pellets. 

Polymer Characterization. Melt-pressed films of the nylon samples were examined using a Nicolett 5DX FTIR. The samples were pressed at 240° C - 260° C at 4,000 to 20,000 psi. Samples in 88% formic acid were precipitated into methanol and also examined as KBR pellets. All samples were scanned a minimum of 100 times. 

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