Plasticisers nylon

Few conclusive studies have identified the source or spread of Brettanomyces within the vineyard except for use of contaminated equipment. Contaminated and improperly sanitized crush equipment, drains, barrels, transfer hoses, valves, pumps, and bottling equipment can all act as sources for further infection (33). Harper (67) found the interior surface of plastic (polyvinyl chloride, polyethene, and plasticised nylon) pipes used commonly in the brewing industry maintained a variety of bacteria and yeast populations, including Brettanomyces. 

By plasticisation. This in effect reduces the Tg and in the case of nylon which has absorbed small quantities of water the toughening effect can be quite substantial. It should, however, be noted that in the case of PVC small amounts of plasticiser actually reduce the impact strength. 

Figure 18.11 shows the influence of temperature on the tension modulus of nylons 66 and 6 and Figure 18.12 the effect of temperature on impact strength of nylon 66. Figure 18.13 shows the profound plasticising influence of moisture on the modulus of nylons 6 and 66, while Figure 18.14 illustrates the influence of moisture content on impact strength. 

Other factors which can affect impact behaviour are fabrication defects such as internal voids, inclusions and additives such as pigments, all of which can cause stress concentrations within the material. In addition, internal welds caused by the fusion of partially cooled melt fronts usually turn out to be areas of weakness. The environment may also affect impact behaviour. Plastics exposed to sunlight and weathering for prolonged periods tend to become embrittled due to degradation. Alternatively if the plastic is in the vicinity of a fluid which attacks it, then the crack initiation energy may be reduced. Some plastics are affected by very simple fluids e.g. domestic heating oils act as plasticisers for polyethylene. The effect which water can have on the impact behaviour of nylon is also spectacular as illustrated in Fig. 2.80. 

Irganox 1010 could be extracted from PP in 18min, using propan-2-ol-cyclohexane (97.5 2.5). For plasticiser extraction from PVC, optimum conditions were hexane-ethyl acetate (60 40) at 170 °C, giving effectively complete extractions after 13 min. For nylon, the optimum conditions were hexane-ethanol (60 40) at 170 °C, and extractions from ground material were 95 % complete after 16 min, including warm-up time. Irganox 1330 was used as an internal standard in PP, n -C1() in... 

Acrylic Sheet (e.g. Perspex) Acrylonitrile Butadiene Styrene Resins (1) Nylon 66 Fibre (m) Nylon 66 Plastics (m) PCTFE PTFE (n) PVDF (y) Rigid Unplasticised PVC Plasticised PVC ... 

Many polymers have been processed by casting, e.g., acrylics, polystyrene, polyamide (nylon 6), phenolics, PVC/plasticiser. Many of these are used in a pre-polymer form, which polymerise on the casting belt, or the polymerisation can be completed later by application of heat. 

More than 90% of all plasticisers are used with PVC, the remainder being used with PVDC, cellulose diacetate, poly(vinyl acetate) (PVAC), nylons, urethanes and acrylates. 

Polyamides (nylons) can absorb water up to a few percent, which acts as a plasticiser (the distance between the chain segments is increased), so that Tg is lowered. Tg is, therefore, dependent on the environment (dry air, moist air or water). The extremes may differ by several tens of degrees. 

Adipic acid Nylon 66, esters, polyurethane resins Fibres, resins, plasticisers, solvents, lubricants Niu etal., 2002... 

The 1930s saw the introduction of the poly generation and the first of many such thermoplastics was poly(vinyl chloride) or PVC which became commercial reality with the introduction of a plasticiser. At about the same time Du Pont Chemicals also launched the polyamide nylon 66 after studying the network structure of silk. A few years later German researchers developed nylon 6 from caprolactam. In the UK, ICI developed and produced polyethylene, a material vital to the success of radar technology during the Second World War. ICI also made a valuable wartime contribution with the development of poly(methyl methacrylate) or PMMA which was used to make shatterproof and protective screens. 

Exchange between product and pack can occur in both directions, e.g. certain labelling materials such as heat sensitive and self-adhesive labels when in contact with plastic materials. Both the plastic and the adhesives may contain plasticisers or migratory constituents. Most cellulosics use phthalate, sebacate, phosphate-type plasticisers (e.g. methyl phthalate (DMP) may be used in cellulose acetate). Plasticisers may also be found in poly vinyl chloride/acetate copolymers, polyvinyl acetate and polyvinyl alcohol formulations, polymethyl methacrylate, nylon and certain thermosetting resins. 

PVC is used in overwrap film, shrink film, shrink sleeving, thermoforming for all types of blister and bubble packs. Plasticised PVC IV bags are usually PP/Nylon overwrapped to reduce moisture loss. 

Poly (hexamethylene adipimide) is also known as Nylon 6,6 since its repeat unit has two six-caibon sequences. Nylon is tough, abrasion resistant, and has a low coefficient of friction, making it a popular suture material. Nylon 6,6 is hydrophilic and absorbs water when placed in tissues or in humid environments (9 to 11 percent water when fully saturated ). Absorbed water acts as a plasticiser, increasing the ductility and reducing the modulus of Nylon 6,6. Nylon bioerodes at a very slow rate. Nylon 6,6 implant in dogs lost 25 percent of its tensile strength after 89 days and 83 percent after 725 days. ... 

Applications of Raman to polymer/additive deformulation are still rather few, especially if compared to IR methods (cfr. Chp. 1.2.1). Hummel [108] has attributed the general lack of applications of RS in the field of plastics additives to poor Raman scattering of certain substance categories, unsatisfactory reproducibility of the spectra and scarcity of specific Raman libraries [385,386]. Polymer/additive analysis by means of Raman spectroscopy is mainly restricted to fillers, pigments and dyes the major usefulness comes from NIR FT-Raman, which greatly overcomes the fluorescence problem. The ion-pair dissociation effect of the 2-keto-4-(2,5,8,11-tetraoxadodecyl)-l,3-dioxolane modified carbonate (MC3) plasticiser in poly(ethylene oxide) (PEO) was studied by means of Raman, FTIR and EX-AFS [387]. Another study established the feasibility of using Raman spectroscopy to quantify levels of melamine and melamine cyanurate in nylons [388]. 

In many cases, such as in the determination of highly volatile materials (e.g. moisture in nylons or in polysaccharides [412]), or of residual solvents or plasticisers (as in PVB) [413], use of TG-MS is requested. Specifically, there are reports on the entrapment of curing volatiles in bismaleimide laminates [414] and elastomers [415], of plasticisers such as bambuterol hydrochloride [416] or triphenyl phosphate and diethylterephthalate in cellulose acetate [417], on solvent extraction and formaldehyde loss in phenolic resins [418,419]. Carraher et al. [420] have used TG-MS to study the degradation of a fluorescent titanium polyether ester dye. 

Quantitative analytical schemes (using calibration curves, internal standardisation) have been devised for selected (copolymeric) systems [540]. An example is the determination of the composition of styrene-methacrylate by PyGC [603]. Qther applications include the quantification of rubber components [604,605], cellulose esters [606], isocyanate components of polyurethanes [607], nylon [608], plasticisers [609], aliphatic sulfur-containing additives [4]. Standardisation for quantitative analysis based on PyGC data requires careful choice of reference polymers. Use of an internal standard may improve the precision when the concentration of a single polymeric component of a blend or copolymer is calculated on the basis of PyGC data [610]. 

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