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Porous Polypropylene Sheets




Porous polypropylene is a material that is highly resistant to most chemicals and reagents. These polypropylene sheets are highly resilient and lightweight, which gives them a wide range of applications. The sheets can be used at temperatures ranging from 93˚C to 129˚C and can be sterilized by steam. The omni-directional and inter-connected pore structure of the sheets makes them perform well in; depth or surface filtration, diffusion or venting of gases, foaming and aeration. Porous polypropylene sheets can be modified by hand tools or conventional machining methods. They are easy to cut and flexible when fabricating.


The porous structure of the sheets make them ideal for filtration and diffusion applications. Due to the porous structure, the sheets are specifically used in industrial filters, fresh and waste water treatment filters, blood serum filters, DNA sampling filters, biomedical filters and pipette tip filters. The interconnected cell structure of the sheets makes them function well in applications such as wicking, filtering and sound muffling. Porous polypropylene sheets are naturally hydrophobic and therefore allow for the wicking of aqueous solutions. Due to the hydrophobic nature, the sheets are specifically applied in; column chromatography, ion exchange resins, battery flame arrestors, liquid reservoirs and fluidized bed air pads


Porous polypropylene sheets have specific usage in material handling applications. They are used in fluidizing beds for powder coating, food processing and bulk pharmaceutical processing. They are also used in fluidizing air pads which assist in the unloading of storage bins/silos and truck hoppers or railroad cars. In addition, porous polypropylene sheets are used in air conveyors to levitate and convey powders such as flour, coatings, pigments, fertilizers, cement and lightweight objects such as films, stampings, semi-conductor chips and electrical components.


The nominal pore size of porous polypropylene sheets ranges from 80 to 125 micrometers. The manufacturers of the sheets combine several types of polymers so as to meet the porosity, heat, strength, abrasion and corrosion requirements of the sheets. The sheets are available in the following sizes: 457mmˣ457mm, 914mmˣ1219mm. The thicknesses of the sheets range from 1.5mm to 6.4mm. Porous polypropylene sheets can be cut and welded with RTV Silicone and M seal.



Polypropylene Resin




Polypropylene (PP) is a thermoplastic polymer (a polymer molded above a given temperature and returns to the solid state upon cooling) used in many applications such as labeling and packaging, textile (e.g. thermal underwear, carpets and ropes), plastic parts, stationery, reusable containers, loudspeakers, polymer banknotes, laboratory equipment and automotive components. It is resistant to many acids, chemical solvents and bases. They are resistant to alkali and organic solvents and does not absorb water and water solutions which are destructive to metals.


Polypropylene is a polymer prepared catalytically from propylene which differs from HDPE by having an isostatic replacement of a hydrogen atom by a methyl group on alternate carbon atoms in the main chain. Although largely unreactive chemically the presence of the methyl groups makes it slightly more susceptible to attach from strong oxidizing agents than HDPE. A major advantage is its higher temperature resistance. It makes it particularly suitable for items such as trays and instrument jars that have to be sterilized frequently for use in a clinical environment. Polypropylene is a translucent material with excellent mechanical properties and it has gradually replaced polyethylene for many purposes.


Benefits of Polypropylene

It is used in the everyday applications because it is semi-flexible. Its melting point is high compared to other plastics. For this reason it is excellent for use in food containers where temperatures can raise to high levels- such as dishwashers and microwaves. Its melting point temperature is 320 degrees F, hence its application in hot containers but should not be used in temperatures higher than 230° F (127° C).


The following are the other benefits of polypropylene:


· It doesn’t absorb water like many other plastics. It is naturally hydrophobic but can be chemically treated to be hydrophilic in porous filtration applications.

· It contains an elastic constituent which provides it with a rubber-like element and makes a way for new uses like bottles and film.

· It does not weaken or mold in the presence of mold, bacteria or other destructive elements. Polypropylene will handle sterilization over and over again where other plastics will not.

· It has low probability of shattering and absorb significant damage before breaking, even though it is not strong compared to other plastics like polyethylene. Polypropylene is more rigid than polyethylene.



Chemical Properties and Uses

Understanding polypropylene is of significance as it differs completely from other types of the plastic products. Its quality properties allow it to be used effectively in the everyday use, especially in situations where a non-toxic and a non-staining material is needed. Its cost is not high. It offers the best alternative to the other plastics as it doesn’t contain BPA which is unsafe for food packaging because it leaches into the food products causing health hazards. Its electric conductivity is low making it suitable for electronic products. As a result of these advantages, polypropylene is used in many American homes.



Autoclavable Test Tube Racks – What You Need To Know






A laboratory is not complete without test tube racks since they are the tools to hold test tubes, an item that is also present in most, if not all laboratories. However, there are certain kinds of laboratories that need to use autoclave as a means to sterilize their tools and equipment. In situations like these, an ordinary test tube rack will not do. What you need is an autoclavable test tube rack. This article is going to focus on the subject of autoclavable test tube racks.


Autoclavable test tube racks works similarly to an ordinary test tube racks with the exception of being autoclavable. The main reason to autoclave your test tube rack is to sterilize it. Sterilizing the racks eliminates the change of bacterial contamination. Keep in mind that an autoclave will expose the racks to high temperatures. That is why autoclavable test tube racks are made from special materials, to withstand such conditions. There are a lot of manufacturers that design and create these kinds of racks; therefore it is best that you do your research before purchasing. Most of the plastic and acrylic racks cannot be autoclaved, so look for a polypropylene rack or a rack constructed of metal.


Autoclavable test tube racks are designed to hold multiple test tubes at once. With your test tube rested nicely on an autoclavable test tube racks, you can expose the test tubes to a wider range of conditions because the materials used in these kinds racks are designed to withstand the extreme conditions your tubes will see.


Additional Things That You Need To Know

Some racks will withstand water baths. These racks need to be heavy to avoid floating and flipping. Most of these racks are manufactured out of metal and therefore can withstand autoclave temperatures.


Autoclavable test tube racks are easy to use and some are storage-friendly. When the time comes that you need them, you can quickly and easily assemble them and when you are done using them you can easily wash them and fold them flat for easy storage. Furthermore, being flat will save you a lot of storage space. Some racks have interlocking feet and are autoclavable with interlocking feet. With this feature, you can easily stack these racks on top of each other tightly and safely.



How Do People Usually Use Pipetting Needles





Pipetting needles are blunt tip needles that have no point. These are widely used for dispensing of fluids because of their accuracy. Blunt tip needles are commonly used in dispensing adhesives, fluxes, lubricants and sealants. The size of the drop dispensed can be adjusted by the gauge of tubing used. The dispensers that use these can be manual applications where liquids are applied from bottles with male luer lock caps or pressurized or manual syringes. In large production these blunt tip needles are used in conjunction with x–y plotters.


Blunt tip needles are available in a variety of lengths because there are times when the liquid that is being dispensed has to be put in places that cannot be reached by hand. Because the female luer hub on these needles is nickel plated brass and the cannula is stainless. Chemicals that are harmful to plastic hubs will not affect these needles. They are also resistant to higher temperatures.


Typical industries that use blunt tip needles are petrochemical, printing, electronic, and circuit board assembly. Medical applications that commonly use blunt tip needles are chromatography, stem cell, pharmacology and animal research. These needles are used because they will not puncture a surface due to the 90° tip. They are also used to connect micro bore tubing by fitting inside the ID of the tubing. Generally, commercial connectors only go down to 1/16” (0.0625”) connections. With blunt tip needles tubing can be glued with cyanoacrylate adhesives to the ID or the OD of the stainless cannula. This allows tubing with ID’s of 0.005” to be attached to male or female connections.



Teflon Sheets



Teflon® sheets are slippery shiny white materials. The characteristic features of Teflon® sheets determine its uses. For instance, they are used in situations where low friction for sliding objects are required. Nevertheless, the following are some of the applications of Teflon® sheets:


Teflon sheets are a multi-functional material mainly used in sublimation and/or heat press industry. Its non-sticky feature makes it important in this industry. Its function is used to prevent ink from staining the platen parts of the heat press machine, thus eliminating the chances of scorching the product and keeps the heat transfers from sticking to the platen. Moreover, Teflon® sheet is used to prevent ghosting effect during sublimation process created when the paper slides across the shirt when the platen is being lifted. It can also be used as a weight to keep the transfer paper in its place to ensure good results. In addition, it can be used with household equipment like hand iron. Teflon® sheets are reusable and can last up to a maximum of 200 presses, hence Teflon® sheets can last for long time.


It is used in beverage, food, and pharmaceutical industries. Teflon® sheets have been approved by Food and Drug organization for use in this industry. This is because the thin film sheets are inert and non-toxic, hence when used to cover food, it cannot react. In addition, it withstands high temperatures. Therefore, Teflon® sheet has the ability to conserve the warmth and maintain the temperature of the covered food for a long time.


Teflon® sheets are excellent electrical resistant, making it suitable for applications in the electrical industry. They are used to provide electrical insulation where it can insulate up to 500 volts per mil.  It is frequently used to wrap electrical wires and cable.  Moreover, it is used to separate conductive plates in capacitors.


Teflon® sheets are used in petrochemical and chemical industries. It is used to make vessel linings, gaskets, rings, pump interiors, dip tubes, washers, seals, spacers, chemical tanks, etc. This is because Teflon® sheets are chemically inert, melts at high temperatures and resistant to corrosion. This makes them unaffected by caustics or acids, and it can be used in high temperature environment of up to 500 degrees Celsius.


In addition, the inert and chemical resistance nature of Teflon® sheets makes it suitable for laboratory applications. Therefore, it is used to make the lining of special pipes, tubes, glasses, vessels and lab counter tops.