Poly yarns

The choice and combinations of different size components must take account of many factors if optimum results are to be obtained. Much has been published regarding the optimisation of size formulations in relation to desizing processes [177-183]. Cotton warp yarns sized with starch are normally woven at high humidity (80% and above) to keep yarn breakages low, as the starch film is brittle at low humidity. It has been shown [183], however, that improved weavability at moderate relative humidity (e.g. 65%) can be obtained using (a) starch/acrylamide or hydroxyethyl starch at not less than 15% add-on or (b) poly(vinyl alcohol), which gave excellent results even at a low add-on of 5-6%. 

Addition of acrylamide to starch improved the performance of cotton yarn more than acrylamide alone, but addition of poly(vinyl alcohol) to starch lowered the performance of the yarn compared with poly(vinyl alcohol) alone. Overall, taking into account economic considerations, stringent pollution requirements and the needs of desizing, the singlecomponent hydroxyethyl starch showed optimum acceptability for weaving performance at moderate relative humidity. 

The poly(ethylene terephthalate-co-esters) were prepared as previously described (9) after knitting, scouring, and deknitting, the yarns were examined, tested and exposed in a standard fashion (9) to 3000 A radiation. 

Photophysical Processes and Photodegradation of Poly(ethylene terephthalate-co-2,6-naphtha1enedi carboxyl ate) Copolymers. We have recently reported the photophysical processes and the photo-degradative behavior of Doly(ethylene terephthalate-co-2,6-naphthalenedicarboxyl ate), PET-2,6-ND, copolymer yarns containing 0.5 - 4.0 mole percent 2,6-naphthalenedicarboxyl ate, 2,6-ND (1) and the parent naphthalenedicarboxyl ate monomer, Figure 3 and 4. 

Figure 4. Effect of radiation on the poly(ethylene terephthalate-co-2,6-naphthalene-dicarboxylate) yarns mole % of 2,6-DMN (%) 0.0 (X) 0.5 fA) 1-0 (O) 2.0 ...

These fibres contain long chains of poly glycols or polyesters between polyurethane blocks. Urethane gets copolymerised with suitable polyol or polyester and then melt spun as monofilament or polyfilament yarn. The urethane blocks are in a randomly disordered fashion in the yarn. When stretched they uncoil and straighten out. 

They also studied the melting characteristics of the powders with surface-grafted MMA polymer by DSC [38]. Grafting of Kevlar 49, or poly(p-phenylene terephthalamide), fiber with GMA and AAm polymers without exposing to air was studied by Yamada et al. [39]. According to their grafting system, Kevlar yarn was suspended in an upper plasma-irradiation vessel and irradiated for 1 min at an Ar gas pressure of 20 Pa, an rf frequency of 13.56 MHz, and an rf power of... 

Polyester. The most common polyester in use is derived from the homopolymer poly (ethylene terephthalate). Many types of this fiber contain a delustrant, usually titanium dioxide. Optically brightened polymers are quite common. The optical brightener, such as specially stabilized derivatives of either stilbenes or phenylcoumarins, can be added to the polyester before formation of the fiber (107). Some commercial fibers contain minor amounts of copolymerized modifier to confer such properties as basic dyeability. A wide range of polyester fibers is used for consumer end-uses. Both staple fiber and filament yarn are available. Filament yarns with noncircular cross-sections are made (107). 

Another important application of thermoplastic fibers such as poly ether ether ketone (PEEK), Poly etherimide(PEI), and VectranM andHS (Vectranis the trade mark of Hoechst liquid crystalline polymer) is in making thermoplastic matrix composites. Commingled yams of the reinforcement and matrix such as quartz/PEEK, glass/PEI, Vectran HS/M are used to make the composites wherein the matrix yarn fuses to form the continuous phase of the composite. 

The nonyl aldehyde coproduct of the azelaic half aldehyde is a useful intermediate after being transformed into the corresponding alcohol, acid, or amine, it is a raw material for plastics. Several years ago, I. Sakurada, Kyoto University, the inventor of Vinylon, found that when nonyl aldehyde is used instead of formalin for acetalization of poly (vinyl alcohol), the properties of Vinylon yarns are considerably improved, especially in elastic recovery. 

The ether group is common in some other a/f-copolymers. Many of these compounds have practical applications. For example, poly(ethylene oxybenzoate) is used as a filament yarn in the silk clothing industry. Other polymers are used as epoxy resins. Several examples of such ether-a/f-different groups are given in Table 9.3.3. Pyrolysis of these macromolecules generates compounds indicative of their composition. 

Fibres and Textiles in Eastern Europe 11, No.l, Jan.-Mareh 2003, p.41-7 ANTIBACTERIAL POLY(ETHYLENE TEREPHTHALATE) YARN CONTAINING CEPHALOSPORIN TYPE ANTIBIOTIC Buchenska J TaAir J Sobolewska E Lodz,Technical University Lodz,Centre of Molecular Macromolecular Studies Lodz,Copernicus Memorial Hospital... 

Whinfield and Dickson quickly realized that the polymer based on ethylene glycol and terephthalic acid was the best suited for fibers (Figure 11). They did, however, make and describe several other polyesters including poly(butanediol terephthalate) (PBT). Many years later a number of polyester fiber producers became interested in PBT. One producer explained that he was interested in PBT because it made a fiber that resembled nylon. Because nylon was becoming popular as a carpet yarn, and because he was not in the nylon business, he considered PBT a means of competing in carpet yarns. 

CH 1 C=N —CH,—CH— 1 C=N poly(acrylonitrile) Orion , Acrilan rugs, blankets, yarn, apparel, simulated fur... 

Blends of PA-66 with some aliphatic-aromatic polyamides of higher T such as poly (hexamethyl-ene isophthalamide) (PA-61) have been evaluated as hbers, in order to achieve improved modulus and heat resistance in PA-66 tire yarn and con-... 

Meanwhile Etliicon (and otiiers) developed alternative absorbable surgical sutures, based, for example, on copolymers of polyglycolide with poly-L-lactide or poly(trimethylene carbonate), and on polydioxanone, and on poly(s-oxycaproate), and also on copolymers of tliese with polyglycolide or with each otlier. These different structures made it possible to provide fibres with different rates of absorption, with different degrees of stiffness or flexibility, and for use in monofilaments, braided multifilaments, and other yarn structures, as required for different surgical operations. 

The triangle shown In Figure 2 shows the Interrelation between the process, the structure of the resulting product, and physical properties. In a modeling situation, one generally starts with a knowledge of the process conditions from which It Is desired to determine structural and physical properties. A study(2) of spinning Poly(ethylene terephthalate) (PET) will be discussed where It was possible to use a model to calculate the stress at the solidification point, and then relate this to spun yarn tensile properties. 

H. Okuzaki, T. Takahashi, N. Miyajima, Y. Suzuki, and T. Kuwabara, Spontaneous formation of poly(p-phenylenevinylene) nanofiber yarns through electrospinning of a precursor. Macromolecules, 39,4276-4278 (2006). 

From the research of Zhang [88], a novel flax yarn waste-g-poly(acrylic acid-co-acrylamide) [FYW/PAA] superabsorbent composite has been synthesized (Fig. 3.6). In order to develop an eco-friendly superabsorbent composite, flax yarn waste (FYW) was used as raw material. Acrylic acid (AA) and acrylamide (AM) were grafted onto the pretreated flax yarn waste (PFYW) by free-radical graft copolymerization in homogeneous aqueous solution. As a result, the prepared FYW/PAA attained the best water absorbency of 875 g/g in distilled water, 490 g/g in rainwater and 90 g/g in 0.9 wt% NaCl solution. 

Wu, F., Zhang, Y, Liu, L., and Yao, J. M. (2012). Synthesis and characterization of a novel cellulose-g-poly(acrylic acid-co-acrylamide) superabsorbent composite based on flax yarn waste, Cgrboh d Ol., 87, 2519-2525. 

FI G U RE 10.44 Clearing temperature (Tc) as a function of polymer concentration for cellulose (DP = 800) in anhydrous phosphoric acid (74.4% w/w P2O5, solid circles). (From Boerstoel, H., Liquid Cystalline Solutions of Cellulose in Phosphoric Acid for Preparing. Cellulose Yarns, Ph.D. dissertation, University of Groningen, 1998.). Open circles represent the clearing temperature for poly(p-phenylene terephthalamide) (M, = 31,000 g/mol) in sulfuric acid (From Picken, S.J., Macromolecules, 22, 1766, 1989.). The square represents the clearing temperature for chitin (Af = 400,000 g/mol) solution at the polymer concentration of 15.5% w/w. 

We have demonstrated this process for the metallization of poly-p-phenylene terephthaiamide films and fibers (Kevlar ) as yarn, woven fabrics, or knit fabrics, as well as poly-m-phenylene isothalamide (Nomex ) as yarn or film. A variety of metals, including silver, copper, and nickel, can be electrolessly plated on aramids in this way, and a variety of activating metals can be substituted for silver. Thick layers (up to -25 )im) of conductive metals can be applied by electrodeposition on top of the metallized aramid. 

Man-made fibres.ThesQdo Qtiihexsynthetic (nylon, poly(ethylene terephthalate), polyacrylonitrile, polypropylene, aramide, etc.) or cellulosics (viscose, cellulose acetate). They are available in the form of continuous yarns (filament, filament yarn) or staple fibres. Inorganic fibres as glass and carbon are also man-made fibres. 

The formation of electrically conductive fibers of polyaniline blended with poly(p-phenylene terephthalamide) processed from sulfuric acid was also reported by Hsu et al. [72]. A thoroughly mixed solution of 0.2 wt% emeraldine base and 17.6 wt% poly(p-phenylene terephthalamide) was dissolved in sulfuric acid and this dope solution was extruded at 80°C through a 20-hole spinneret into a 1°C water coagulation bath. The continuous 20 filament yarns that were collected on the bobbin were thoroughly washed with water, which probably led to partial deprotonation of the emeraldine salt. However, the... 

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