Abstract:
Disclosed herein is a mixture of at least one semi-aromatic polyamide A) and at least one semi-aromatic polyamide B), both containing repeat units derived from terephthalic acid. Further disclosed herein are a polyamide molding composition including said mixture of polyamides, a molded article produced from said polyamide molding composition and a method of using the mixture of semi-aromatic polyamides for the production of a molded article with improved mechanical properties, in particular with improved weld line strength.
Abstract:
A structural element with a controllable heat transfer coefficient comprises a frame. A first sheet and a second sheet opposite one another are arranged in the frame. The sheets and the frame have the effect of defining a closed-off volume which is filled with at least one gas. At least one two-dimensional element is arranged between the sheets. An upper intermediate space is formed between the two-dimensional element and the frame vertically upwardly and a lower intermediate space is formed between the two-dimensional element in the frame vertically downwardly. A first cavity is between the first sheet and the two-dimensional element. A second cavity is between the two-dimensional element and the second sheet. The cavities are connected via the upper intermediate space and the lower intermediate space such that a convection flows between the cavities via the intermediate spaces. At least one means arranged in the intermediate spaces controls the convection flow.
Abstract:
A process for producing a melamine-formaldehyde foam by heating and foaming an aqueous mixture M using microwave radiation, said mixture M comprising at least one melamine-formal-dehyde precondensate, at least one curative, at least one surfactant, at least one blowing agent and at least one linear polymer with a number average molecular weight Mn in the range from 500 to 10.000 g/mol and at least two functional groups selected from OH, NH2 or COOH as well as a melamine-formaldehyde foam obtainable by this process and its use.