fbpx

Cicloturismo

Il blog dedicato al cicloturismo ed ai viaggi in bicicletta

Scopri tutti gli articoli sul cicloturismo

Ultimi Articoli

Rimani in contatto

Seguici sui social

  • ganilynd ha inviato un aggiornamento 1 anno, 11 mesi fa

    Ultra High Molecular Weight Polyethylene (UHMWPE) is odorless, tasteless and nontoxic. It was first aggregated in the 1950s. The first ultra-high molecular weight polyethylene (UHMWPE) fibers were commercialized in the late 1970s. It has extremely long polyethylene chains, all aligned in the same direction. Its molecular weight is as high as 3.5-7.5 million amu, which is much higher than that of polyester yarn with a molecular weight of about 20,000. When used in fibers, the degree of parallel orientation of the polymer chains can be greater than 95%, and the degree of crystallinity is 39% to 75%.

    UHMWPE has a simple molecular structure and possesses some surface and chemical properties that other high-performance polymers do not possess. For example, UHMWPE is less absorbent and less hygroscopic because its olefins do not contain polar groups. It also makes it difficult to combine with other polymers. For the same reason, the skin does not interact strongly with it, so UHMWPE fibers are very slippery. Since UHMWPE contains no chemical groups such as esters, amides or hydroxyl groups, it is highly resistant to water, moisture, most chemicals, UV radiation and microorganisms.

    UHMWPE yarn has higher crystallinity and molecular weight, better thermal conductivity, can transfer heat quickly and achieve super cooling effect. UHMWPE fibers are resistant to water, moisture, most chemicals, UV radiation and microbes, giving you more protection.

    FAQ:
    CAN ADHESIVES BE USED TO SECURE UHMW LINERS?
    Not for most applications. The reason is the large difference between the coefficient of thermal expansion of metal and UHMW puts high stresses on the bond if the bond encounters temperature extremes.
    WHAT ARE MY INSTALLATION OPTIONS FOR UHMW?
    There are two methods of adhering 鈥?the use of pressure sensitive systems (peel and stick) and allowing UHMW-PE to be bonded using epoxy systems or contact cements. A traditional metal mechanical fastening can also be used if preferred.
    CAN UHMW BE FORMED INTO A CURVED LINER?
    Bending or folding sheet can be done efficiently above the melt point at 300 degrees F. At that temperature, it shapes easily. However, it must be fastened in the bent or folded position until cooled.
    HOW THICK SHOULD UHMW LINERS BE?
    The minimum UHMW thickness is usually 1/4鈥? The liner should be thicker in impact areas and thinner in slide areas. Important notes: UHMW cannot be firmly fastened to metals because of a large difference in thermal expansion. UHMW expands five times as fast as steel and three times as fast as aluminum and about the same as wood but slightly more than concrete.
    WHAT IS THE BEST WAY TO SECURE UHMW LINERS TO METAL?
    Fasteners are the best way to secure UHMW to metal. The UHMW must be allowed to expand or float. Large flat head fasteners must be used. Fastener shaft holes in UHMW must be over-sized to allow for sheet expansion and contraction.UHMWPE Fabric factory
    website:http://www.impact-fibers.com/uhmwpe/uhmwpe-fabric/