A preform made from two different materials that do not bond together by a bi-injection process, using the same mold, is presented. An outer layer of the preform can be first made, then an inner layer molded through a center hole in a bottom of the outer layer, and the two layers connected. Inner/outer preform materials can be different, such as PET/polyolefin or polyamide, or the same, such as PET/PET. To prevent mutual bonding during molding of the second layer, a non-stick coating may be sprayed onto a surface portion of the first layer prior to molding the second. In embodiments, manufacturing order can be either outer/inner, or inner/outer, and the non-stick coating sprayed on the inside/outside of the layer first molded.

A method for joining thermoplastic composite components is provided that includes: providing a first thermoplastic composite (FTC) component having an FTC first zone and an FTC second zone; providing a second thermoplastic composite (STC) component having an STC first zone and an FTC second zone; forming a joint region between the FTC and STC components by disposing them in a stepped arrangement, wherein each material ply within the FTC first zone overlaps a material ply within the STC first zone by a first overlap distance, and at least one material ply within the FTC second zone overlaps a material ply within the STC second zone by a second overlap distance, and at least one material ply within the FTC second zone overlaps a material ply within the STC second zone by the first overlap distance; and joining the FTC and STC components by applying an elevated temperature and pressure.

A nasal/oral cannula for collecting a flow of exhaled gases and its method of manufacture are disclosed. The cannula comprises an elongated tubular body having a first and a second end portion, a surface and an internal volume; a wall internally disposed within said tubular body, said wall defining a first subvolume of said internal volume in the lengthwise direction of the tubular body; and an inlet through said surface, for introducing exhaled gases into said first subvolume. The first end portion defines an exit port for exhaled gases from said subvolume, and said wall is arranged directly adjacent to said inlet.