Any undesirable modification of the properties of a material caused by the essential actions of organisms is called Bio-deterioration. This article deals with the degeneration of textile materials produced by microorganisms such as fungi and bacteria and solutions to avoid or reduce their effects.
All failures of materials by microorganisms are not desired. When we throw away objects that are no longer needed, we wait for "Nature" to evacuate what has become waste. Such deterioration is a vital process for the protection of the world in which we live, and it is a process of recycling many vital components contained in these materials. However, it can be a critical problem for manufacturers and users when it is an undesirable process, when textiles are influenced by rot or mold.
Under suitable environment, microorganisms that inhabit soil, water and air can grow and flourish on textile materials. These organisms include species of microfungi, bacteria, actinomycetes (filamentous bacteria) and algae. Textiles made from natural fibers are normally more vulnerable to biodeterioration than synthetic synthetic fibers. Microbial expansion can also be advanced by products such as starch, protein derivatives, fats and oils used in the finishing of textiles. Microorganisms may attack the entire substrate, ie, the textile fibers, or attack a single constituent of the substrate, such as the plasticizers therein, or push on accumulated dirt on the surface of the substrate,
However, even a minor surface tumor can make an ugly tissue by the appearance of an unwanted pigmentation. An intense infestation, which causes decomposition and failure of the fibers and consequent physical variations such as loss of firmness or flexibility, can produce tissue that does not serve. The material is chemically attacked by the action of extracellular enzymes produced by the microorganism for the purpose of acquiring food. However, microbial activity can be reduced by saving the dryness of vulnerable materials, as the expansion of the surface will only occur when the relative humidity is high. Therefore, a kind of chemical shield is usually required with textiles that should be used under hostile conditions under which they remain wet or damp for a long time.
Vegetable fibers such as cotton, flax (linen), jute and hemp are very vulnerable to attacks of cellulolytic fungus (cellulose digesters). Of course, complete cellulose degeneration can be achieved by enzymes created by fungi and recognized as cellulases. Diagram 1 gives details of the chemical process involved. The spores of these microfungi are there in the atmosphere and when they are placed on suitable substrates, they can grow rapidly under conditions of temperature and humidity. The typical form of growth of these molds is recognized as mold, growing outward, which can discolor and spoil the fabric with the stain, as many microfungi are capable of producing pigments. The best protection against mold is to ensure that the fabrics are dry when stored and do not become wet in the cellar. Fabrics that are used outdoors for awnings, beach umbrellas, military uniforms, sails, tarpaulins, tents, truck and boat covers, shoes and shoe linings are Treated with a fungicidal finish to save them from mold. Greening algae can also appear on fabrics that remain moist for a long time and can create special problems in the tropics.
In proportion to the vegetable fibers, the animal fibers are less affected by the growth of mildew. Pure silk, so completely degummed, is less vulnerable. Wool decomposes only slowly, but chemical and mechanical damage during the process can increase its vulnerability to biodeterioration.
Synthetic or artificial fibers
Synthetic fibers obtained from synthetic or artificial fibers Cellulose are vulnerable to microbial degeneration. Viscose (rayon) is easily hit by mold and bacteria; Acetate and triacetate are not affected, although discoloration can occur if the tissues are stored incorrectly. The fibers produced from synthetic polymers (eg, acrylic, nylon, polyester, polyethylene and polypropylene fibers) are highly resistant to attack by microorganisms.
The hydrophobic nature of these polymers is probably an important aspect determining their resistance. Furthermore, these synthetic polymers have chemical bonds that do not occur or are rare in nature and therefore may not have been long enough for the microorganisms to develop the appropriate enzymes needed to begin their analysis. Although the substance of a synthetic fiber itself is not resistant to microbial development, low molecular weight pollutants (eg, the remaining marks of nylon 6 caprolactam monomer) and mixtures such as lubricants and Spinning oils used in the finishing of textiles can give satisfactory results Nutritive for the smooth surface evolution of the fabric, A microorganism. In most cases, this does not influence the health of the tissue, but may lead to discoloration and discoloration, which are often not easy or impossible to eliminate
Different types of plastics have surfaced as sections of textile products, for example, to provide impermeable coatings for impermeable garments. Plastics, which are produced mainly or entirely from polymers such as polyethylene, are generally very resistant to microbial expansion. However, two types of plastics used significantly as coatings for textile materials, polyvinyl chloride (PVC) and polyurethanes, are vulnerable to bio-deterioration. In the case of PVC, the polymer itself does not readily provide a nutrient medium for bacteria and fungi. The vulnerability of PVC formulations to microbial attack is associated with the amount and types of plasticizers, fillers, pigments and stabilizers etc. inserted during processing. Many of these additives are relatively low molecular weight organic compounds. For example, plasticizers (mainly esters of organic acids, polyesters and chlorinated hydrocarbons), used to improve the flexibility of an otherwise fragile polymer, will in most cases Feeding microbial expansion and their degree of vulnerability has a profound impact on the propensity of the textile coating to biodeterioration; Such microbial use of plasticizers may cause cracking of the PVC coating during use. With polyurethanes, on the other hand, the actual polymer is able to support microbial evolution because of the resemblance of some of the chemical connections in polyurethanes to those discovered in nature.
Use of Biocides
The perfect technique for preventing microbial degeneration is to use synthetic materials that are naturally resistant to microbial degradation attack. Another method is to apply antimicrobial chemicals known as "biocides" which are generally included in the finished textile product. So far, no additive agent has been unearthed, which offers neither total safety nor any inconvenience. Perfect biocides include the following requirements:
. Effective against a wide range of microorganisms, especially bacteria and microfungies
. Operational during the life of the product.
. Low toxicity to mammals and non-toxic to humans at concentrations used.
. Lack of color and odor.
. Influence at low concentrations
. Cheap and easy to use.
. Resistant to sunlight and percolating from the fabric.
. Handle tissue and health are not affected.
. Suitable for use with repellent and flame retardant agents, dyes and other textile accessories
It would be an endless journey if someone sets out to find the ideal biocide and the compromise choice of a suitable product is not always easy. Some chemicals, such as organo-mercuric compounds, have been discarded due to their long-lasting and increasing toxic effects in the environment. Textile materials, which must be used outdoors, need a constant fungicide that has rain-washing properties and the ability to suffer from light failure. If the environment is extremely damp, monitoring of algae and bacteria becomes more important.
The biocides used regularly in the textile industry are organo-copper compounds, organotin compounds and chlorinated phenols. These work by intervening in the energy production procedures of microbial cells. Copper naphthenate and copper-8-hydroxyquinolinate are widely versatile, highly effective biocides against fungi, bacteria and algae. They are specially used to handle textiles that may be naked on the ground and to severe weather conditions, Examples are cotton and linen fabrics, awnings, tarpaulins, ropes, ropes, bags, tents, military uniforms and military apparatus. The main disadvantage is that they give a yellow-green color to the processed materials. Pentachlorophenol esters, conventionally pentachlorophenyl laurate (LPCP), are resistant to percolation by rainwater and are therefore applied as fungicides for spreading a wide range of textiles with cotton , Linen and jute fabrics used as lids, tarpaulins, blinds, tents, etc .; Coated fabrics, hospital materials, mattress covers, pressed felts and woolen fabrics. Some biocides may provide more than one goal; Thus, the organotin mixtures can function as stabilizers for both plastic formulations as well as fungicides.
The use of biocides in tissues for decomposition and mold testing is generally carried out as a final finishing treatment. The fabric is soaked either in a solvent solution (usually white spirit) or, more commonly, in an emulsion of the biocide; It is then pressed and dried using a cylinder dryer, stent or other suitable tools. The fabric can be polished first, but more usually and specially with heavy materials, the biocides are applied to a polishing loom material. Very often they are co-applied with water repellent, flame retardant and pigment. In vinyl polymers such as PVC, the biocide is generally diffused into the plasticizer, which is generally the most biodegradable component. As the surface film is removed, new plasticizer will move to the surface, taking with it a continuous source of biocide. However, these products ultimately lose their protective merits by seasoning even though 70% to 80% of the biocide continues to be chemically unaffected in the formulation. One possible cause is that under the influence of heat and ultraviolet radiation, depolymerization of the vinyl resin and subsequent crosslinking can condense the biocide, verifying its transfer to the surface where biodeterioration occurs.
Give hygienic finishes for fabrics that will be used in health care products. These finishes are classified as renewable or durable, although the long finishes are gradually detached during laundry. Renewable finishes may be substituted during bleaching, for example quaternary products
ammonium compounds used to resist the eruption of the towel.
It is not easy to measure the extent of biological degradation of textile materials, but it is also possible to provide some protection against responsible microfungies Of the athlete's foot for hygienic finishes applied to socks and coatings. It must be estimated in terms of millions of pounds sterling per year in the United Kingdom alone. Breaking materials can often be a complicated event resulting from a mixture of chemical, physical and microbiological reasons. The problem is more important with the fabrics used outdoors, but other products such as floor coverings, carpet racks, shower curtains, vinyl baby pants, and mattresses may also need to be worn, Antimicrobial finish to check fungal and bacterial surface expansion. If possible, choose materials naturally resistant to microbial attack rather than materials that need to be protected. Thus, synthetic products, which resist mildew, struggle positively with cotton in the manufacture of sails for boats or shower curtains. Prior research is needed on the production techniques of natural and synthetic materials that are more resistant to bio-deterioration by chemical alteration of their make-up, especially as uncertainties have now been raised as to Toxicity and environmental constancy of some of the well-known biocides. It is also expected that improved biocides will appear on the market to meet a new set of laws introduced by governments concerned about the environmental impact of the current compounds.
Source by Gaurav Doshi