Hals | Svensk Porr

Hals | Svensk Porr
One of the most important classes of antioxidant for long-term heat protection of
polymers are the so called hindered amine light stabilizers (HALS) which are very effective inhibitors against free
radical induced degradation of polymers at low and medium temperatures. This class of amine stabilizers is based on 2,2,6,6-tetramethyl-piperidine derivatives. They are often employed as light stabilizers, particularly for olefins which explains their naming.
HALS can be categorized according to their molecular weight (MW): HALS with low molecular weight of about 200 to 500 g/mole are commonly referred as low MW HALS, while those with a molecular weight of 2000 or
higher are referred as high MW HALS. These two classes have different rates of diffusion in the polymer matrix, which is an important factor in protecting polymers from UV radiation. In general, high MW HALS are
more effective long-term heat stabilizer than low MW HALS, whereas very low MW HALS do not provide much thermal stability at all. The efficiency of HALS can also be greatly affected by the structure, i.e. side
groups, and sometimes by the formulation and surface conditions. To maximize the light stability of plastics, the most suitable HALS structure must be chosen.
Photo-oxidation usually starts at the surface with visible cracks, which leads to rapid degradation of the mechanical properties. In theory, olefins such as polyethylene (PE) and polypropylene (PP) are stable
when exposed to sunlight, because both C-C and C-H bonds do not absorb UV radiation from the sun. However, there are always contaminations
present like residual catalyst, pigments, and thermal degradation by-products
from melt processing of the resins that can initiate photo
degradation of any polyolefin when exposed to UV light, which, in
turn, causes chain scission and/or crosslinking and eventually surface cracking and
loss of mechanical properties.
The high efficiency of HALS is based on a complex set of free-radical scavenging reactions, which starts with the oxidation of HALS to nitroxide radicals (RNO·) by
reaction with peroxides or
hydroperoxides (see figure above), which subsequently react with polymeric alkyl radicals, yielding hydroxylamine ethers which can react with a variety of compounds. New RNO· radicals may be regenerated from the
reaction of hydroxylamine ethers with alkylperoxy and acylperoxy radicals
(Denisov cycle).
The oxidation of HALS to the NO· radicals is a relatively slow
and temperature-dependent reaction. Furthermore, they are not very
efficient at elevated temperatures (above 80°C or so), thus, they
are not very effective processing stabilizers. For this reasons, HALS are often used in combination with primary and secondary antioxidants . This combination may also show
synergistic or antagonistic effects. Due to these unpredictable effects, complex mixtures are often used. For this reason, the study of interactions between stabilizers from different chemical classes is
of great
importance.
Hindered amine light stabilizers or short HALS are very effective antioxidant for long-term
protection of plastics against photo-oxidation.
The most widely used HALS are derivatives of
2,2,6,6-tetramethyl-piperidine.
In general, high molecular weight HALS are more
effective long-term heat stabilizers than low molecular
weight HALS. However, they are less reactive.
HALS are continuously regenerated, which explains their high effectiveness for long term heat stabilization.
HALS are not very effective processing stabilizers.
For this reason, they are often used in combination
with primary and secondary antioxidants, like hindered
phenols.
Key data on over two hundred and fifty polymers.
Properties of commercial commodity and engineering polymers.
Physical and mechanical properties of polymers
Support CROW Polymer Properties Database to improve its content.

Great Food. Great Beer. Great Atmosphere.
Hal’s Bar & Grill is a locally owned and operated bar and restaurant located in the North Hills of Pittsburgh with strong ties to the community. Hal’s quickly became a neighborhood favorite—perfect for friends, couples, groups and families alike. People often refer to Hal’s as a chill, comfortable atmosphere with a down home feel.
Hal’s offers a large amount of TVs for the sports enthusiast to watch all of their favorite games—inside and outside on the patio. Don’t be fooled, you may initially think you will be dining at a sports bar, but Hal’s will surprise you. While they are widely known for their wings, Hal’s offers a diverse menu with a few unique twists. You will find your favorite bar food items such as Nachos Grande, Fried Pickles and Spinach Artichoke Dip but you will also discover some exciting, albeit uncommon, items such as Meatloaf Cupcakes, Grilled Lamb Chops, Ahi Tuna and Pork Osso Buco, to name a few. The extensive craft beer selection is also a great attraction. Hal’s takes pride in featuring a wide variety of local beers and breweries.
Christmas time at Hal’s is a magical experience. For the last 5 years, Hal’s has displayed a larger-than-life tree on the patio. They kick off the holiday season with a Tree Lighting Ceremony complete with a countdown to light the tree, a Make-your-own S’mores Bar, hot chocolate and even a visit from Santa to take photos with the kids.
People go to Hal’s for the food and the atmosphere but they come back because they feel like they are a part of a community. Dine at Hal’s today!
2021 Tree Lighting ceremony is on Tuesday, 11/ 30 at 7:30 pm. Come early for kids games & activities, write a letter to Santa, enjoy hot chocolate & more! The tree will be lit at 7:30 with a fireworks display.
We are known for our wings, but don’t hesitate to check out some of the other popular menu items. New this season: Nashville Hot Chicken Sandwich, Short Rib Flatbread, Gyro & more.
Outdoor dining is currently unavailable. The patio will be open for dining in the Spring.
3225 Babcock Blvd Pittsburgh, PA 15237
Monday – Thursday: 4pm – 12am Friday: 4pm – 1am Saturday: 12pm – 1am Sunday: 12pm – 11pm
The kitchen closes 1 hour before closing time
We are closed on major holidays including Easter, Memorial Day, 4th of July, Labor Day, Thanksgiving, Christmas Eve, Christmas Day & New Years Day
halsbarandgrill@yahoo.com 412-364-3230

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Hal’s Beverage LLC
Maspeth, NY 11378
info@halsnewyork.com

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