Melt spinning extrusion process

Suture manufacture is specialized. In the production from raw materials or isolation from natural materials, purification is especially important because small amounts of by-products and contaminants can have a serious effect of the properties of the suture and the behavior within the patient. Processes for suture fabrication include melt spinning, extrusion, and braiding. 

Extrusion Processes. Polymer solutions are converted into fibers by extmsion. The dry-extmsion process, also called dry spinning, is primarily used for acetate and triacetate. In this operation, a solution of polymer in a volatile solvent is forced through a number of parallel orifices (spinneret) into a cabinet of warm air the fibers are formed by evaporation of the solvent. In wet extmsion, a polymer solution is forced through a spinneret into a Hquid that coagulates the filaments and removes the solvent. In melt extmsion, molten polymer is forced through a multihole die (pack) into air, which cools the strands into filaments. 

The dyeing of polypropylene fibers, being an item of research for decades, is successfully accomplished with partially stearate-modified hyperbranched polyesteramides. The long alkyl chains ensure compatibility with the polypropylene matrix. The mixing-in of hyperbranched polyesteramides via extrusion affected neither the melt spinning process nor the final polypropylene fiber properties. The modified fibers are dyeable under standard conditions as are, e.g., polyesters or cotton. They can even be used for printing for example a picture pattern on a polypropylene carpet. 

The alloys are first produced by rapid solidification and are amorphous in nature. They are either directly fabricated as powders, by a process such as high-pressure gas atomisation (HPGA), or by melt-spinning of ribbons, which are subsequently pulverised to form a powder (<150 /im). The powders are then consolidated by hot extrusion between 950-1050°C where the initial amorphous structure breaks down and forms a fine dispersion of stable borides in a ductile Fe-based matrix. 

The process of cellulose regeneration in the form of lyocell fibers is significantly simpler than that of the viscose rayon process. It is illustrated in O Fig. 16. A solution containing 14% cellulose, 10% water, and 76% NMMO plus stabilizers is extruded at a temperature slightly above 100 °C into an aqueous NMMO-bath from which cellulose is precipitated [74,75]. The extrusion has been described as a melt-spinning process that has recently made it possible to manufacture cellulosic self-bonded meltblown nonwovens as well [76]. 

Important processing methods melt spinning, injection molding, extrusion... 

Important processing methods injection molding, extrusion, wire coating, mixing, melt spinning... 

PLA and PHB may be processed because of their thermoplastic properties in the usual thermoplastic processing systems by using extrusion, injection molding, melt spinning, blowing film, and melt-blown techniques. 

A comfortable pathway for improvement of the crystallization of poly(3-hydroxybutyrate) in a melt-spinning process is the use of nucleating agents like electron-beam irradiated PHB [28] or the reactive extrusion with peroxide [29]. 

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