What is the WLF equation used to calculate?
What is the WLF equation used to calculate?
The WLF equation is typically used to describe the time/temperature behavior of polymers in the glass transition region. The equation is based on the assumption that, above the glass transition temperature, the fractional free volume increases linearly with respect to temperature.
What is WLF equation in polymer chemistry?
1 William-Landel-Ferry (WLF) Equation. where ε0=strain at reference temperature, T0=reference temperature, t=time, ε=strain at an arbitrary temperature, T=arbitrary temperature and aT=shift factor. For amorphous polymers, the WLF equation applies to temperature range varying from Tg to about Tg+100°C.
How do you calculate the Tg of a polymer?
Tg is typically calculated by using a half-height technique in the transition region. The heating rate and sample heat history are a couple of factors that may affect the test result. Depending on the equipment capability, DSC can be used for a wide range of thermoplastic and thermoset polymers.
What is free volume theory?
According to the free-volume theory, the rate of molecular diffusion is based on the amount of free space or free-volume between the molecules and was first used to describe the diffusion in liquids.
What is the WLF last of us?
The Washington Liberation Front (WLF or W.L.F.), informally called Wolves, are a militant paramilitary organization and a major antagonistic faction in The Last of Us Part II. They are located in Seattle, and are currently at war with the Seraphites for control of the area.
What is the glass transition temperature?
Glass transition temperatures are very variable ranging from 140 °C to 370 °C according to the grades, curing process and the moisture content: For a defined grade, the glass transition temperature increases from 50 °C during post cure.
What is the full form of WLF?
| WLF | Washington Legal Foundation Governmental » Law & Legal — and more… |
|---|---|
| WLF | Department of Wildlife and Fisheries Governmental » State & Local |
| WLF | Wolfson Microelectronics Business » Companies & Firms |
| WLF | Wisconsin Lions Foundation Community » Non-Profit Organizations |
| WLF | Women’s Leadership Forum Community |
What is Tg value?
The value of Tg depends heavily on the mobility of the polymer chain, and for most synthetic polymers lies between 170°K and 500°K (-103°C and 227°C). Pure crystalline polymers do not have a glass transition temperature because the glass transition temperature is only applicable to amorphous polymers.
What is Tg and TM in polymers?
The terms TG (or Tg) and TM (or Tm) give two important parameters of polymers. These are temperatures at which the texture of polymer changes. These values are characteristic features of polymers. TG refers to the glass transition temperature whereas TM refers to the melting temperature.
How do you calculate free volume?
D ln t = B’ (1/f – 1/f0) where f0 is the fraction free volume at a reference temperature such as the glass transition temperature and f is the free volume at a temperature of interest. The free volume at a temperatur eof interest, f, is given by free volume theory (above) as f = f0 + af (T – T0).
Do Plasticizers increase free volume?
Plasticizers are involatile, low molecular weight molecules that can modify the polymer matrix, increasing free volume and chain mobility.
Is WLF a firefly?
At some point prior to 2028, the WLF crossed paths with the Fireflies. The two groups held an amiable relationship, enough that Isaac extended an offer to accept members of the group into the WLF if they ever desired to join. Tommy Miller also met the group, learning their name, location, insignia and dress code.