WHAT MATERIALS ARE CURRENTLY USED TO MAKE A THERMOS AND WHY?

Often current thermos are made out of two layers (Glass & Vacuum) to decrease the amount of heat escaping, a rubber support so that conduction doesn't occur, and a shiny interior coat around the outside layer of the bottle. The shiny coat is used to lessen the amount of thermal radiation. Some other materials that could be used to make a thermos could be,

• 2L Bottle 
• Plastic bottle
• Tin foil
• Foam layer
• Duct tape
• Steel wool
• Sock
• Rice
• Clay
• Bubble
• Wrap

2L Bottle & plastic bottle: The 2L bottle is for containing the plastic bottle as well as to preserve the heat of the inner insulation. The plastic bottle is for the liquid to be poured in and to preserve heat as well.

• These two layers are nestled together at the neck and all the air in between them is evacuated.
• A reflective coating is added to the surfaces of both layers so that radiative heat loss can be minimized.

Tin foil: The tin foil will be going inside the 2L bottle and around the plastic bottle so that the heat keeps circulating and the heat content isn’t being lost but reflected.
 

http://answers.yahoo.com/question/index?qid=20071230112658AAtLlY2
 

Foam layer & Steel wool: The foam layer and steel wool will act as the main insulator. The foam layer can’t conduct air because of its plastic pockets, thus heat/cold temperatures can’t be release easily.  Steel wool is used in many industrial places for high heat insulation; this proves that steel wool can retain heat as it’s been tested and used numerous times.

http://steelwooldirect.com/insulation/

http://wiki.answers.com/Q/Why_is_plastic_foam_a_good_insulator
 

Duct tape: To keep everything together as well as add extra insulation

http://answers.yahoo.com/question/index?qid=20091124152439AAXpLIv
 

Rice: To secure materials together, and get rid of extra crevices that is not needed.

• This material could be used for the bottom of the thermos to prevent conduction

Cotton sock: to maintain the steel wool or any other materials and to add extra insulation. Cotton traps air which build up in heat.

http://wingtip.com/wool-vs-cotton-socks

http://wiki.answers.com/Q/Why_cotton_is_a_good_insulator#page2

Bubble Wrap: Contains patches of trapped air which is a good insulator, as temperatures can’t be transferred.

http://wiki.answers.com/Q/How_is_bubble_wrap_a_good_insulator

Clay: The minerals in clay have low thermal conductivity so it’s a good heat insulator. Which is why we choose this for the top cover of our thermos. 

• Since most of the heat loss in a thermos occurs through the neck and opening of  the flask, the openings are usually stoppered with cork, polyethylene plastic or rubber that is attached to the lid to prevent any additional heat loss. 

http://answers.yahoo.com/question/index?qid=20100107222756AALF6q1