pH – It is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions (solutions with higher concentrations of H+ ions) are measured to have lower pH values than basic or alkaline solutions.
To calculate the pH of an aqueous solution you need to know the concentration of the hydronium ion in moles per liter (molarity). The pH is then calculated using the expression: pH = – log [H3O+].
We also learnt about the pH scale which measures the acidity or alkalinity of a substance. The pH scale goes from 1-14, with pH7 being completely neutral, i.e water. Anything with a very low pH is acidic, while substances with a high pH are alkaline.
Phr– Phr abbreviation stands for parts per hundred rubber.
Phr might refer to parts per hundred rubber, a measure used by rubber chemists to depict what amount of certain ingredients are needed, especially PR vulcanization.
To calculate phr, first convert the resin amount to 100 g. (5*20=100 g) Now, multiply the amine weight by 20 (20*1.24 = 24.8). So, the phr is about 25.
If you want to double check your phr calculation:
PMQ – Comparatively, replacing the methyl groups with phenyl groups allows the silicone to withstand drastically lower temperatures. PVMQ, (FC for ASTM) phenyl modified silicones exhibit a lower temperature resistance by almost 100°C, with a working service temperature of -177°C. Once again, it’s not common to use silicone without vinyl groups but the process can also apply to MQ creating PMQ.
PACKING, MECHANICAL– Mechanical and compression packing consists of various combinations of fibres, yarns and lubricants. … Many yarn types are used to make general packing (e.g., graphite, carbon, PTFE, acrylic, aramid, fibre glass, cotton). However, when considering packing for use in valves, the number of materials is more limited.
If there are no fluids available to lubricate, the seal runs dry which causes extra friction and heat. The seal will burn or melt and become damaged, which causes fluid leakage due to the pressure. Even a few seconds of dry running can cause heat cracks or blisters, which leads to a leaking pump shaft seal.
The purpose of a mechanical seal is to prevent leakage, but all seals leak to some controlled degree. However, it is important to note that this minimal leakage can be so restricted that specific designs are capable of adequately meeting all emission requirements. Seal failure is defined as excessive leakage.
PALE CREPE– Pale latex crepe (PLC) is a premium grade, made from raw field latex. … Re-milled crepe is made from “wet slab coagulum” (cured latex, still wet from the coagulation tanks), latex sheets (unsmoked) and cup lump. Smoked blanket crepe is made from thick sheets of latex that have been processed in a smoker.
Crepe, or Plantation Rubber, is a natural material that’s predominantly made from latex tapped from trees like the Pará rubber tree. … Now a solid material, the sheets of Crepe Rubber are then sent to manufacturers—such as Clarks or Yuketen—to be cut into soles for shoes and boots.
Grades of crepe rubber depends on quality of crepe rubber sheets. Also quality of sheets depends on several factors such as quality of latex, amount of formic acid adding, , coagulation time, washing quality ( using more water in the milling section can make higher grade crepe ), drying time.
PARAFFINS– Paraffin is a by-product of oil purification process and often comes in colourless solid wax type substance. … It comes in liquid form as mineral oils which are used in beauty creams and lotions, while paraffin wax is used in beauty salons and spa treatments for manicures, pedicures and cuticle care.
Most candles today are made of paraffin wax which creates highly toxic benzene and toluene when burned (both are known carcinogens). In fact, the toxins released from paraffin candles are the same as those found in diesel fuel fumes and are linked to asthma and lung cancer.
When burned, paraffin wax can release toxic volatile organic compounds (VOCs) into the air including acetone, benzene and toluene, which are known carcinogens. These are the same chemicals found in diesel fuel emissions and are known to cause allergies, asthma attacks and skin problems.
PASTE – Paste adhesives have high viscosities to allow application on vertical surfaces with little tendency to sag or drip. These bodied adhesives can serve as gap fillers and sealants.
PEPTIZER– Peptizers serve as either oxidation catalysts or radical acceptors, which essentially remove free radicals formed during the initial mixing of the elastomer. This prevents polymer recombination, allowing a consequent drop in polymer molecular weight, and thus the reduction in compound viscosity.
PERFORMANCE TEST – Federal law requires manufacturers and importers to test many consumer products for compliance with consumer product safety requirements.
PERMANENT SET – the amount by which a material stressed beyond its elastic limit fails to return to its original size or shape when the load is removed.
PEROXIDE– Peroxide, any of a class of chemical compounds in which two oxygen atoms are linked together by a single covalent bond. Several organic and inorganic peroxides are useful as bleaching agents, as initiators of polymerization reactions, and in the preparation of hydrogen peroxide (q.v.) and other oxygen compounds.
Peroxides, such as hydrogen peroxide. In peroxides, oxygen has an oxidation number of -1. When oxygen is combined with fluorine, its oxidation number is +2.
PHASE– The three fundamental phases of matter are solid, liquid, and gas (vapour), but others are considered to exist, including crystalline, colloid, glassy, amorphous, and plasma phases. When a phase in one form is altered to another form, a phase change is said to have occurred.
Substances on Earth can exist in one of four phases, but mostly, they exist in one of three: solid, liquid or gas. Learn the six changes of phase: freezing, melting, condensation, vaporization, sublimation and deposition.
A phase diagram is a graph which shows under what conditions of temperature and pressure distinct phases of matter occur. The simplest phase diagrams are of pure substances. These diagrams plot pressure on the y-axis and temperature on the x-axis.
PHENOLIC– Phenolic is an adjective and a substantive (noun) that may apply to : Phenol (or carbolic acid), a colorless crystalline solid and aromatic compound. Phenols, a class of chemical compounds that include phenol. Phenolic content in wine. Phenolic paper, a type of cardboard used for printed circuit boards.
Phenols are widely used in household products and as intermediates for industrial synthesis. For example, phenol itself is used (in low concentrations) as a disinfectant in household cleaners and in mouthwash. Phenol may have been the first surgical antiseptic.
Phenol is highly irritating to the skin, eyes, and mucous membranes in humans after acute (short-term) inhalation or dermal exposures. Phenol is considered to be quite toxic to humans via oral exposure. … EPA has classified phenol as a Group D, not classifiable as to human carcinogenicity.
PIGMENT– Pigmentation means coloring. Skin pigmentation disorders affect the color of your skin. Your skin gets its color from a pigment called melanin. Special cells in the skin make melanin. When these cells become damaged or unhealthy, it affects melanin production.
PLANTATION RUBBER– natural rubber grown especially in the Malay Peninsula, Indonesia, and Sri Lanka chiefly from a Brazilian tree (Hevea braziliensis) imported into those areas.
PLASTIC FLOW, OR DEFORMATION– Plastic flow is a rheological phenomenon in which flowing behavior of the material occurs after the applied stress reaches a critical value (yield). … This slope and the weight of the ice induce a shear stress throughout the mass. When subjected to a shear stress over time, ice will undergo creep, or plastic deformation.
Deformation and flow, in physics, alteration in shape or size of a body under the influence of mechanical forces. … Flow is a change in deformation that continues as long as the force is applied.
Flow rule. In metal plasticity, the assumption that the plastic strain increment and deviatoric stress tensor have the same principal directions is encapsulated in a relation called the flow rule.
PLASTICITY- Plasticity, ability of certain solids to flow or to change shape permanently when subjected to stresses of intermediate magnitude between those producing temporary deformation, or elastic behaviour, and those causing failure of the material, or rupture (see yield point).
Plasticity, ability of certain solids to flow or to change shape permanently when subjected to stresses of intermediate magnitude between those producing temporary deformation, or elastic behaviour, and those causing failure of the material, or rupture (see yield point).
Neuroplasticity – or brain plasticity – is the ability of the brain to modify its connections or re-wire itself. … For example, there is an area of the brain that is devoted to movement of the right arm. Damage to this part of the brain will impair movement of the right arm.
PLASTICIZER– A plasticizer is an additive that is added to another material (usually a plastic or an elastomer) to make that material softer or more pliable.
Plasticizers increase the flow and thermoplasticity of a polymer by decreasing the viscosity of the polymer melt, the glass transition temperature (Tg), the melting temperature (Tm) and the elastic modulus of the finished product without altering the fundamental chemical character of the plasticized material.
A plasticizer (UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, or to decrease friction during its handling in manufacture.
PLASTISOL– Plastisol is used as ink for screen-printing onto textiles. Plastisols are the most commonly used inks for printing designs onto garments, and are particularly useful for printing opaque graphics on dark fabrics.
Plastisol is a PVC-type coating in plasticizing liquids. … At room temperature, Plastisol is a liquid; when heated or cured, the liquid turns to a flexible, rubber-like barrier. Once applied, Plastisol coating is practically indestructible, making it ideal for numerous high-impact applications.
A substance consisting of a mixture of a resin and a plasticizer that can be molded, cast, or made into a continuous film by application of heat.
PLASTOMETER– An instrument for measuring plasticity or viscosity (as of rubber).
PLATEAU EFFECT– The plateau effect is a force of nature that lessens the effectiveness of once effective measures over time. An example of the plateau effect is when someone’s exercise fails to be as effective as in the past, similar to the concept of diminishing returns.
A plateau is a flat, elevated landform that rises sharply above the surrounding area on at least one side. Plateaus occur on every continent and take up a third of the Earths land. They are one of the four major landforms, along with mountains, plains, and hills.
The Piedmont Plateau of the Eastern United States between the Appalachian Mountains and the Atlantic Coastal Plain is an example. Continental plateaus are bordered on all sides by plains or oceans, forming away from the mountains. An example of a continental plateau is the Antarctic Plateau in East Antarctica.
PLATEN– A platen (or platten) is a flat platform with a variety of roles in printing or manufacturing. It can be a flat metal (or earlier, wooden) plate pressed against a medium (such as paper) to cause an impression in letterpress printing.
The platens heat the mold and should be at least the size of the mold you want to run. The larger the platen, the larger the mold you can run. A platen size of 16″ x 16″, for example, will result in 256 square inches of surface area. A platen size of 32″ x 32″ will result in 1024
The platen tube superheater consists of a series of heat exchange surfaces, each of which has a wall-like appearance, set across a horizontal section of the flue gas duct, so that the flue gas flows between each of the platen ‘walls’. … In terms of heat exchange, platen superheaters are regarded as convective types.
PLY– A ply is a layer of material which has been combined with other layers in order to provide strength. The number of layers is indicated by prefixing a number.
PLY ADHESION– While ply adhesion is defined as the force required to separate two adjoining plies, the reality is that ply adhesion is the force required to pull apart the adhesion that joins the plies. This is measured in pounds per inch or newtons per millimeter.
POLYBLEND– Poly-blend, originally, referred to combining two or more different poly materials to make a separate material. … This method creates a textile which is a blend of both polyester and natural fibres. The more popular examples of these would be poly-cotton, linen blends or terrycot.
Polyblend is a granular material of recycled modified plastic, plastic film waste, plastic conveyor bag waste or plastic packing material which is mixed with bitumen and used for road laying. Polyblend and bitumen strengthen the bitumen-water-repellent properties when used to lay roads and help to improve road life.
Polyblend is a fine powder of recycled modified plastic. It was produced by plastic manufacturers in order to recycle plastic waste. When blended with bitumen, polyblend can be used to lay roads which have increased road life.
POLYBUTADIENE– Polybutadiene [butadiene rubber BR] is a synthetic rubber. Polybutadiene rubber is a polymer formed from the polymerization of the monomer 1,3-butadiene. Polybutadiene has a high resistance to wear and is used especially in the manufacture of tires, which consumes about 70% of the production.
Most polybutadienes are made by a solution process, using either a transition metal (Nd, Ni, or Co) complex or an alkyl metal, like butyllithium, as catalyst.
POLYMER– A polymer (/ˈpɒlɪmər/; Greek poly-, “many” + -mer, “part”) is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life.
Polymers are used in almost every area of modern living. Grocery bags, soda and water bottles, textile fibers, phones, computers, food packaging, auto parts, and toys all contain polymers. Even more-sophisticated technology uses polymers.
Natural polymers (also called biopolymers) include silk, rubber, cellulose, wool, amber, keratin, collagen, starch, DNA, and shellac. … Examples of synthetic polymers include PVC (polyvinyl chloride), polystyrene, synthetic rubber, silicone, polyethylene, neoprene, and nylon.
POLYMER CHAIN– A carbon atom bonded to 2 hydrogen atoms can be considered a building block or unit of the polymeric chain. … These units make up monomers, which are repeating units in the molecular chain structure. A series of monomers bonded together to form a molecular chain is known as a polymer.
Monomer means one part. A polymer is made up of a number of joined-together monomers. One way of thinking about polymers is like a chain of connected-up paperclips. A polymer is a large molecule made up of smaller, joined-together molecules called monomers.
Assorted combinations of heat, pressure and catalysis alter the chemical bonds that hold monomers together, causing them to bond with one another. Most often, they do so in a linear fashion, creating chains of monomers called polymers.
POLYMERIZATION– Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds.
Polymerization is a process through which a large number of monomer molecules react together to form a polymer. … Polyethylene, which is one of the most commercially important polymers, is prepared via such a polymerization process (the reactant monomer used here is ethylene).
Polymerization is the process to create polymers. These polymers are then processed to make various kinds of plastic products. During polymerization, smaller molecules, called monomers or building blocks, are chemically combined to create larger molecules or a macromolecule.
POST CURE– Post curing is the process of exposing a part or mold to elevated temperatures to speed up the curing process and to maximize some of the material’s physical properties. This is usually done after the material has cured at room temperature for at least 12 hours.
Heat curing refers to an industrial practice of using high temperature resins, chemicals, rods or other fluids to harden a polymer by facilitating the cross-linking of polymer chains. … Heat curing may also be known as thermal curing.
The degree of curing describes the conversion achieved during crosslinking reactions (curing). Linkage can be achieved either by direct setup of macromolecules or reaction to the already existing polymers. … This can easily be measured by means of differential scanning calorimetry (DSC).
For most concrete structures, the curing period at temperatures above 5º C (40º F) should be a minimum of 7 days or until 70% of the specified compressive or flexural strength is attained. The period can be reduced to 3 days if high early strength concrete is used and the temperature is above 10º C (50º F).
POUND-VOLUME– An easy method to compare compounds of the same hardness is to multiply the specific gravity by the cost per pound. The result is known as the pound/volume cost
PRECURE – Its raw popularity in terms of viewing figures and income is because it is (usually) decent kids’ TV in a good timeslot. I hear it sells a lot of toys. Being what it is, Precure tends to have a fairly simple monster-of-the-week plot which builds up towards a grand finale.
perform, execute, discharge, accomplish, achieve, effect, fulfill mean to carry out or into effect. perform implies action that follows established patterns or procedures or fulfills agreed-upon requirements and often connotes special skill.
The preform consists of a fully formed bottle/jar neck with a thick tube of polymer attached, which will form the body. similar in appearance to a test tube with a threaded neck. The preform mold opens and the core rod is rotated and clamped into the hollow, chilled blow mold.
PREPOLYMERS– Polyether polyols’ major use is in polyurethane foams. Flexible foams are primarily used in cushioning applications such as furniture, bedding and car seats, and in carpet underlay. Rigid foam’s largest consumer is the construction industry where it is mostly used for insulation.
Prepolymers are frequently used in injectable two-component systems to improve handling properties or reduce toxicity. Isocyanate-terminated prepolymers are prepared by reacting an excess of a polyisocyanate with a polyol at 60–90 °C in the presence of a urethane catalyst, such as dibutyltin dilaurate.
PRESS CURE– Press vulcanization takes place in presses that supply pressure and heat. A very simple mold consists of two metal plates with cavities which conform to make the outside shape of the desired finished part. The presses hydraulically pushes plates heated by electricity steam or hot oil together vulcanizing the rubber.
PRIMER– A primer (/ˈpraɪmər/) or undercoat is a preparatory coating put on materials before painting. Priming ensures better adhesion of paint to the surface, increases paint durability, and provides additional protection for the material being painted.
Surface coatings are used to protect the surface of magnesium and its alloys to prevent their direct contact with air and moisture so that the electrochemical corrosion reactions described above will not occur or occur at a very low rate.
PROCESSABILITY– Processability signifies the overall cost of any material, starting from its raw material to the final product. … The mechanical strength of the material defines the usability in a high shearing condition.
PROOFED GOODS – Fabrics that have been coated with rubber by spreading rubber solution or dough on the surface.
PURE GUM STOCK– Rubber compounding involves the science and engineering of rubbers and rubber additives, such as processing aids, fillers, and curing agents, in definite proportions to obtain a uniform mixture that will have desirable physical and chemical properties to meet processing at low cost and end use performance.
The two most common elements found in natural rubber are carbon and hydrogen. … Styrene-butadiene rubber is the most common synthetic rubber because of how cheap it is to produce. Styrene and butadiene are combined and react to form a compound, which is 25 percent styrene and the rest that is comprised of butadiene.
The main chemical constituents of rubber are elastomers, or “elastic polymers,” large chainlike molecules that can be stretched to great lengths and yet recover their original shape. The first common elastomer was polyisoprene, from which natural rubber is made.
Panel – A coal mining block that generally comprises one operating unit.
Panic bar – A switch, in the shape of a bar, used to cut off power at the machine in case of an emergency.
Parting – The layer of slate or stony coal that separates two benches of a coal seam.
Parting – (1) A small joint in coal or rock; (2) a layer of rock in a coal seam; (3) a side track or turnout in a haulage road.
Pavement – The bottom of the floor of any excavation.
Peat – An unconsolidated deposit of semi-carbonized plant remains of a water-saturated environment, such as a bog, and of persistently high moisture content (at least 75%). It is considered the early stage or rank in the development of coal.
Peat Coal – A coal transitional between peat and brown coal or lignite.
Percentage extraction – The proportion of a coal seam which is removed from the mine. The remainder may represent coal in pillars or coal which is too thin or inferior to mine or lost in mining. Shallow coal mines working under townships, reservoirs, etc., may extract 50%, or less, of the entire seam, the remainder being left as pillars to protect the surface. Under favorable conditions, longwall mining may extract from 80 to 95% of the entire seam. With pillar methods of working, the extraction ranges from 50 to 90% depending on local conditions.
Percussion drill – A drill, usually air powered, that delivers its energy through a pounding or hammering action.
Permissible – That which is allowable or permitted. It is most widely applied to mine equipment and explosives of all kinds which are similar in all respects to samples that have passed certain tests of the MSHA and can be used with safety in accordance with specified conditions where hazards from explosive gas or coal dust exist.
Permit – As it pertains to mining, a document issued by a regulatory agency that gives approval for mining operations to take place.
Piece Can – The underground workman’s lunch container, usually made from sheet metal, with a tea can made from the same material.
Piggy-back – A bridge conveyor.
Pillar – An area of coal left to support the overlying strata in a mine; sometimes left permanently to support surface structures.
Pillard and Bord – The name used to describe a mining method (i.e. coal is extracted from the bords and left in the pillars). The latter’s extraction is the final mining process.
Pillar robbing – The systematic removal of the coal pillars between rooms or chambers to regulate the subsidence of the roof. Also termed “bridging back” the pillar, “drawing” the pillar, or “pulling” the pillar.
Pinch – A compression of the walls of a vein or the roof and floor of a coal seam so as to “squeeze” out the coal.
Pinch – A compression of the roof and floor of a coal seam so as to “squeeze” out the coal.
Pinning – Roof bolting.
Pit – A mine.
Pitch – The inclination of a seam; the rise of a seam.
Plan – A map showing features such as mine workings or geological structures on a horizontal plane.
Pneumoconiosis – A chronic disease of the lung arising from breathing coal dust.
Portal – The structure surrounding the immediate entrance to a mine; the mouth of an adit or tunnel.
Portal bus – Track-mounted, self-propelled personnel carrier that holds 8 to 12 people.
Post – The vertical member of a timber set.
Powder – Explosive chemical in powder form used at the coal face to blast.
Preparation plant – A place where coal is cleaned, sized, and prepared for market.
Primary roof – The main roof above the immediate top. Its thickness may vary from a few to several thousand feet.
Primer (booster) – A package or cartridge of explosive which is designed specifically to transmit detonation to other explosives and which does not contain a detonator.
Prop – Coal mining term for any single post used as roof support. Props may be timber or steel; if steel–screwed, yieldable, or hydraulic.
Proximate analysis – A physical, or non-chemical, test of the constitution of coal. Not precise, but very useful for determining the commercial value. Using the same sample (1 gram) under controlled heating at fixed temperatures and time periods, moisture, volatile matter, fixed carbon and ash content are successfully determined. Sulfur and Btu content are also generally reported with a proximate analysis.
Pyrite – A hard, heavy, shiny, yellow mineral, FeS2 or iron disulfide, generally in cubic crystals. Also called iron pyrites, fool’s gold, sulfur balls. Iron pyrite is the most common sulfide found in coal mines.
Pumpman – A workman who maintains and supervises a pump’s operation.