Should your paraffin be polymer free
Paraffin wax is a mixture of straight chain hydrocarbons. Most manufacturers are adding plastic polymer resins to their paraffin wax. This hardens the tissue. Polymers were added to paraffin many years ago in response to insufficient infiltration in open processors, due to xylene and alcohols absorbing water from the atmosphere. Insufficient infiltration causes tissues and plastic polymers harden the block.
Improvements in tissue processors have significantly reduced water contamination in xylene and alcohols. Most modern processors provide reagent management capabilities to keep reagents pure.
benefits of mediate pure paraffin
- Tissues cut like butter
- No need to mix paraffin when polymers sink to the bottom
- No white precipitate polymer clumps in your embedding center
- Polymer free paraffin is excellent for both infiltration and embedding
Translucent color makes small biopsies easy to embed
Definition of wax
Waxes are organic substances that are solid at room temperature but become free-flowing liquids at slightly higher temperatures.
The chemical composition of waxes is complex, but normal Alkanes are always present in high proportion, and molecular weight profiles tend to be wide. The main commercial source of wax is crude petroleum, but not all crude oil refiners produce wax. "mineral" wax can also be produced from lignite, plants, animals and even insects produce materials sold in commerce as "wax."
beeswax yellow beeswax is secreted by bees to build honeycombs; the empty comb is melted in boiling water to recover the wax. Yellow beeswax can be bleached with oxidizing agents to white beeswax, a product favored in the cosmetic industry. The composition of beeswax varies widely with geography and the diet of the bees forming the combs.
other animal based waxes include lanolin from the wool of sheep, and ambergris, produced in the intestines of sperm whales. Another example of animal waxes that have been traded in the past is spermaceti, derived from the head oil of the sperm whale. Of course, the endangered status of the whale has stopped trading in this product and resulted in the development of synthetic substitutes. One of the most enduring qualities of the wax business has been the ability to improvise and develop substitutes in the face of supply disruptions.
carnauba wax is recovered from a variety of palm tree which grows almost exclusively in northeastern Brazil. Carnauba wax forms on the fronds of the trees and is recovered by cutting and drying the fronds, then mechanically removing the wax. Impurities are removed from the wax by melting and filtering or centrifuging. Carnauba wax is distinguished by its hardness and high melt point, combined with an ability to disperse pigments such as carbon black, properties which make carnauba useful in printing inks. It is also used to gel organic solvents and oils as a component of solvent and paste formulations. Carnauba polishes to a high gloss, and is used to polish items such as leather products, candies, metal surfaces, etc.
candellila wax is harvested from shrubs grown in the Mexican states of Coahuila and chihuahua and in texas. The entire mature plant is uprooted and immersed in boiling water acidified with sulfuric acid; the wax floats to the surface for recovery. Principal markets for candelilla wax include cosmetics, food and pharmaceuticals.
other vegetable based waxes include japan wax, produced on the berries of a small tree native to japan and china; ouricury wax, obtained from the fronds of another palm tree growing in Brazil; rice-bran wax, extracted from crude rice bran; and jojoba, obtained from the seeds of the jojoba plant grown in parts of costarica, Israel, Mexico and the united states.
Most of the waxes described so far can be characterized by a higher degree of difficulty required to recover and purify them in significant quantity. Waxes derived from petroleum are much easier to recover, and offer a wide range of physical properties that can often be tailored by refining processes. Most producers offer two distinct types of petroleum waxes: paraffin, distinguished by large, well formed crystals and microcrystalline , higher melting waxes with small, irregular crystals. Some producers also sell intermediate" wax, the boiling range cut where the transition in crystal size and structure occurs. Petroleum wax producers also characterize wax by degree of refinement: fully refined paraffin has oil content generally less than .5%, and fully-refined micro-crystalline less than 1.5% slack wax - precursors to the fully refined versions in either case would have oil content above 2 and as high as 35% by weight. Paraffin wax produced from petroleum is essentially a pure mixture of normal and Iso-Alkanes without the esters, acids, etc. Found in the animal and vegetable-based waxes. Micro crystalline wax contains substantial proportions of branched and cyclic saturated hydrocarbons in addition to normal Alkanes
synthetic waxes have entered the wax market in the past 50 years. Polyethylene waxes are low molecular weight polyethylene having wax-like properties made by either high-pressure or low-pressure polymerization. All such waxes have the same basic structure, but the various production processes yield products with distinctly different properties, and these have a major impact on the use of products. Products from one manufacturer may satisfy one particular application, while product from a similar process will not work well at all. Major uses include hot-melt adhesives for applications requiring high-temperature performance, additives to improve the processing of plastics, and slip and rub additives for inks, paints and cosmetics