Polyester resins combine excellent mechanical, electrical and thermal properties with very good chemical resistance and dimensional stability.
Chemical resistance of polyester to some common products:. Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro. We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience. Some of our calculators and applications let you save application data to your local computer.
Tag Search en: polyester chemical resistance. Search the Engineering ToolBox. Privacy We don't collect information from our users. Citation This page can be cited as Engineering ToolBox, Polyester - Chemical Resistance. Modify access date. Scientific Online Calculator.Polyesters are one of the most important classes of thermoplastic polymers. They can be formed from the reaction of a diacid or acid anhydride and a diol with the elimination of water, or by ring-opening polymerization of cyclic di- esters.
According to the composition of their main chain, polyesters are classified as aliphaticsemi-aromatic and aromatic see table below. Aromatic reactants improve the hardness, rigidity, and heat resistance, whereas aliphatic acids and diols increase the flexibility, lower the melting or softening point and improve the processability.
Common aliphatic diols are ethylene glycol, 1,4-butanediol, and 1,3-propanediol. They are often reacted with aromatic diacids, such as terephthalic acid, phthalic acid, phthalic anhydride and naphthalene dicarboxylic acid.
Glycerol and unsaturated acids anhydrides like maleic anhydride, are sometimes added to crosslink the polyesters. In the case of unsaturated acids anhydridescrosslinking is achieved in a subsequent free radical chain polymerization.
Double bonds in the backbone of the polyesters also improve the resistance to softening and deformation at elevated temperatures. A large number of polyesters exist due to the numerous possible combinations of dialcohols and diacids.
However, only a small number have gained commercial significance. Both are semi-aromatic and are either amorphous when solidified by rapid cooling or semi-crystalline when solidified slowly.
Both polyesters can be easily molded or thermoformed and have many attractive properties, like high strength and toughness, good abrasion and heat resistance, low creep at elevated temperatures, good chemical resistance and excellent dimensional stability, particularly when glass-fiber reinforced. Another important polyester is polyethylene naphthalate PEN. PEN usually surpasses PET in top end demanding applications and is often a good and less expensive alternative to polyimides.
Completely aliphatic polyesters, made from aliphatic diacid and aliphatic diol components, are produced on a much smaller scale. They have low melting or glass transition temperatures and poor hydrolytic stability. They are mainly used as low-molecular-weight plasticizers and as prepolymer reactants in the synthesis of polyurethanes. A few other aliphatic polyesters are known for their biocompatibility and biodegradability, and their capability to be blended with various other commercial polymers.
Polycaprolactone PLC has good water, oil, and solvent resistance. This polymer is often blended with other resins to improve their processing and end use properties. It can also be blended with starch to lower cost and to increase the biodegradability.
PLC resin blends are also used as a feedstock for injection-molding of disposable articles like drinking cups and food containers. However, the market share of biodegradable polymers is rather small but is expected to grow.Chemically, polyester is a polymer primarily composed of compounds within the ester functional group.
Most synthetic and some plant-based polyester fibers are made from ethylene, which is a constituent of petroleum that can also be derived from other sources. While some forms of polyester are biodegradable, most of them are not, and polyester production and use contribute to pollution around the world.
Use of polyester in apparel reduces production costs, but it also decreases the comfortability of apparel. When blended with cotton, polyester improves the shrinkage, durability, and wrinkling profile of this widely-produced natural fiber. Polyester fabric is highly resistant to environmental conditions, which makes it ideal for long-term use in outdoor applications.
The fabric we now know as polyester began its climb toward its current critical role in the contemporary economy in as Terylene, which was first synthesized by W.
Carothers in the UK. Throughout the s and s, British scientists continued to develop better forms of ethylene fabric, and these efforts eventually garnered the interest of American investors and innovators. Polyester fiber was originally developed for mass consumption by the DuPont Corporation, which also developed other popular synthetic fibers like nylon.
During World War II, the Allied powers found themselves in increased need of fibers for parachutes and other war materiel, and after the war, DuPont and other American corporations found a new consumer market for their synthetic materials in the context of the postwar economic boom. Initially, consumers were enthusiastic about the improved durability profile of polyester compared to natural fibers, and these benefits are still valid today.
What is Polyester Fabric: Properties, How its Made and Where
In recent decades, however, the harmful environmental impact of this synthetic fiber has come to light in great detail, and the consumer stance on polyester has changed significantly. Apparel that contains polyester, however, will melt in extreme heat, while most natural fibers char.
Molten fibers can cause irreversible bodily damage. The production processes used to make polyester may vary depending on the type of polyester is made:.
Ethylene polyester PET is the most commonly-produced form of polyester fiber. The primary component of PET is petroleum-derived ethylene, and in the process of creating polyester fiber, ethylene serves as the polymer that interacts with other chemicals to create a stable fibrous compound.
There are four ways to make PET fiber, and the polyester production process varies slightly depending on which method is used:. Filament: Polyester filaments are continuous fibers, and these fibers produce smooth and soft fabrics. Staple: Polyester staples resemble the staples used to make cotton yarn, and like cotton staples, polyester staples are usually spun into a yarn-like material. Tow: Polyester tow is like polyester filament, but in polyester tow, the filaments are loosely arranged together.
Fiberfill: Fiberfill consists of continuous polyester filaments, but these filaments are produced specifically to have the most possible volume to make bulky products like pillows, outerwear, and stuffing for stuffed animals. The process of creating polyester fiber begins with reacting ethylene glycol with dimethyl terephthalate at high heat.
This reaction results in a monomer, which is then reacted with dimethyl terephthalate again to create a polymer. This molten polyester polymer is extruded from the reaction chamber in long strips, and these strips are allowed to cool and dry, and then they are broken apart in to small pieces. The resulting chips are then melted again to create a honey-like substance, which is extruded through a spinneret to create fibers. Depending on whether filaments, staple, tow, or fiberfill fibers are desired, the resulting polyester filaments may be cut or reacted with various chemicals to achieve the correct end result.
In most applications, polyester fibers are spun into yarn before they are dyed or subjected to other post-production processes.Polyester is a category of polymers that contain the ester functional group in their main chain. As a specific materialit most commonly refers to a type called polyethylene terephthalate PET.
Polyesters include naturally occurring chemicals, such as in the cutin of plant cuticlesas well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradablebut most synthetic polyesters are not. The material is used extensively in clothing. Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties.
Cotton -polyester blends can be strong, wrinkle- and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire-resistant and can melt when ignited. Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are used for their mechanical properties and heat-resistance.
These traits are also important in their application as an abradable seal in jet engines. Natural polyesters could have played a significant role in the origins of life. Depending on the chemical structure, polyester can be a thermoplastic or thermoset. There are also polyester resins cured by hardeners; however, the most common polyesters are thermoplastics. The OH group is reacted with an Isocyanate functional compound in a 2 component system producing coatings which may optionally be pigmented.
Polyesters as thermoplastics may change shape after the application of heat. While combustible at high temperatures, polyesters tend to shrink away from flames and self-extinguish upon ignition.
Polyester fibers have high tenacity and E-modulus as well as low water absorption and minimal shrinkage in comparison with other industrial fibers. Unsaturated polyesters UPR are thermosetting resins.
They are used in the liquid state as casting materials, in sheet molding compoundsas fiberglass laminating resins and in non-metallic auto-body fillers. They are also used as the thermoset polymer matrix in pre-pregs.
Fiberglass-reinforced unsaturated polyesters find wide application in bodies of yachts and as body parts of cars. Increasing the aromatic parts of polyesters increases their glass transition temperaturemelting temperature, thermal stabilitychemical stability They are then used as prepolymers. Fabrics woven or knitted from polyester thread or yarn are used extensively in apparel and home furnishings, from shirts and pants to jackets and hats, bed sheets, blankets, upholstered furniture and computer mouse mats.
Industrial polyester fibers, yarns and ropes are used in car tire reinforcements, fabrics for conveyor belts, safety belts, coated fabrics and plastic reinforcements with high-energy absorption. Polyester fiber is used as cushioning and insulating material in pillows, comforters and upholstery padding.Polyethylene terephthalate sometimes written poly ethylene terephthalatecommonly abbreviated PETPETEor the obsolete PETP or PET-P, is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods, thermoforming for manufacturing, and in combination with glass fibre for engineering resins.
PET consists of polymerized units of the monomer ethylene terephthalate, with repeating C 10 H 8 O 4 units. Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous transparent and as a semi-crystalline polymer.
The monomer bis 2-hydroxyethyl terephthalate can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct this is also known as a condensation reactionor by transesterification reaction between ethylene glycol and dimethyl terephthalate DMT with methanol as a byproduct. PET preform for injection stretch blow moulding of a bottle.
PET clamshell packagingused to sell fruit, hardware, etc. Plastic bottles made from PET are widely used for soft drinks see carbonation. For certain specialty bottles, such as those designated for beer containment, PET sandwiches an additional polyvinyl alcohol PVOH layer to further reduce its oxygen permeability. Biaxially oriented PET film often known by one of its trade names, "Mylar" can be aluminized by evaporating a thin film of metal onto it to reduce its permeability, and to make it reflective and opaque MPET.
These properties are useful in many applications, including flexible food packaging and thermal insulation such as space blankets. Because of its high mechanical strength, PET film is often used in tape applications, such as the carrier for magnetic tape or backing for pressure-sensitive adhesive tapes. Non-oriented PET sheet can be thermoformed to make packaging trays and blister packs. Color-conferring dyes can easily be formulated into PET sheet. When filled with glass particles or fibresit becomes significantly stiffer and more durable.
PET is also used as a waterproofing barrier in undersea cables. Terylene a trademark formed by inversion of polyeth ylene ter ephthalate is also spliced into bell rope tops to help prevent wear on the ropes as they pass through the ceiling. PET is used since late as liner material in type IV composite high pressure gas cylinders.
PET in its natural state is a colorless, semi-crystalline resin. Based on how it is processed, PET can be semi-rigid to rigid, and it is very lightweight. It makes a good gas and fair moisture barrier, as well as a good barrier to alcohol requires additional "barrier" treatment and solvents.
It is strong and impact-resistant.
PET becomes white when exposed to chloroform and also certain other chemicals such as toluene. Clear products can be produced by rapidly cooling molten polymer below T g glass transition temperature to form an amorphous solid. At room temperature the molecules are frozen in place, but, if enough heat energy is put back into them by heating above T gthey begin to move again, allowing crystals to nucleate and grow.
This procedure is known as solid-state crystallization. When allowed to cool slowly, the molten polymer forms a more crystalline material. This material has spherulites containing many small crystallites when crystallized from an amorphous solid, rather than forming one large single crystal.
Light tends to scatter as it crosses the boundaries between crystallites and the amorphous regions between them. This scattering means that crystalline PET is opaque and white in most cases. Fiber drawing is among the few industrial processes that produce a nearly single-crystal product. Intrinsic viscosity is dependent upon the length of its polymer chains but has no units due to being extrapolated to zero concentration.
The longer the polymer chains the more entanglements between chains and therefore the higher the viscosity. The average chain length of a particular batch of resin can be controlled during polycondensation.
The intrinsic viscosity range of PET: . Monofilament, engineering plastic. PET is hygroscopicmeaning that it absorbs water from its surroundings.Small shops are more careful about purchases and production. Some continually producing small runs throughout the year and others but only twice a year. Larger retailers have sales more often. Find retail sale listings at www.
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Whether you are considering NSX or an experienced user, there is something in this session for you. He is a recognized Software Defined Data Center and VMware expert with key certifications including VCAPs in multiple tracks, and VCIX-NV. John has over 19 years of technology experience and his specialties include network and server virtualization, cloud computing, networking, and enterprise storage.
We will also discuss troubleshooting approaches which will help you identify, resolve, and avoid issues during an Install and Upgrade. We will provide an overview of the vCenter Server Appliance Migration feature in vSphere 6. We will also share the top issues you may encounter, how to identify and resolve these, and share tips on how to avoid them during a migration. You will receive a high level look at the features in vSphere 6. We will also discuss the latest vSphere 6. This is a hands-on class designed to help you and your organization realize all the benefits of updating your existing vSphere infrastructure to vSphere 6.
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What is the role of each vRealize Automation component. What are the tools available to troubleshoot vRealize Automation.Example: 2 category optional The category that best describes the logistic regression.
Example: "This is a description of my new logistic regression" eps optional Stopping criteria for solver. If the difference between the results from the current and last iterations is less than eps, then the solver is finished. Example: false name optional The name you want to give to the new logistic regression. Example: "my new logistic regression" normalize optional Whether to normalize feature vectors in training and predicting.
Example: "l1" replacement optional Whether sampling should be performed with or without replacement. Example: 1000 tags optional A list of strings that help classify and index your logistic regression. This will be 201 upon successful creation of the logistic regression and 200 afterwards.
Make sure that you check the code that comes with the status attribute to make sure that the logistic regression creation has been completed without errors.
This is the date and time in which the logistic regression was created with microsecond precision. True when the logistic regression has been built in development mode. The list of fields's ids that were excluded to build the logistic regression.
The list of input fields' ids used to build the logistic regression. It includes a list of coefficients and the field's dictionary describing the fields and their summaries. See here for more details. Specifies the list of ids of the field that the logistic regression predicts.
In a future version, you will be able to share logistic regressions with other co-workers or, if desired, make them publicly available. The alternative key that gives read access to this logistic regression.
This is the date and time in which the logistic regression was updated with microsecond precision. Statistical tests to assess the quality of the model's fit to the data. This makes each field have roughly equivalent influence.
Example: true category optional The category that best describes the cluster. G-means iteratively takes existing clusters and tests whether the cluster's neighborhood appears Gaussian. If it doesn't the cluster is split into two. The default is to 5, which seems to work well in most cases.Lactide Polyester Resins as Tackifiers in EVA Hot Melt Adhesive Applications
A range of 1 - 10 is acceptable.