Tunable multi-layer thermoplastic polymer sealants and tunable two-layer conductive thermoplastic polymer sealants, and substrates and assemblies comprising the tunable multi-layer sealants; and edge seals and fillet seals produced comprising such sealants; and substrates, components and objects comprising the tunable edge seals and fillet seals, and methods for making and applying such edge seals and fillet seals are disclosed.

A method of forming a self-sealing fuel tank includes: providing a container including internal surfaces and external surfaces and configured to hold a fuel; forming a latex coating layer over at least a portion of the internal surfaces and/or external surfaces; depositing or encapsulating an environmental layer over at least a portion of the latex coating layer; where the latex coating layer swells when contacted with the fuel; and where the latex coating layer is formed from a latex coating composition that is substantially free of a non-ionic associative thickener.

A fuel head assembly for a fuel tank has a fuel head body, an inlet connector, an inlet tube, an overflow tube, and a fuel level sensor. An upper end of the fuel body has an inlet port, a sensor port, an overflow port, and a vent port. The lower end of the fuel head body is connectable to the fuel tank. The inlet connector is connected to an upstream end of the inlet port. The inlet tube is connected to a downstream end of the inlet port. The inlet tube extends into the fuel tank. The overflow tube is connected to the overflow port. The fuel level sensor is positioned in the fuel sensor port and has a portion extending into the fuel tank.

A fuel tank comprising a tank and a venting system is disclosed. The tank comprises a housing defining a tank cavity and a port defined in the housing in communication with the tank cavity. The venting system comprises a base attached to the housing, wherein the base defines a base cavity in fluid communication with the tank cavity through the port and a relief housing movably connected to the base, wherein the relief housing is movable between a first position and a second position, wherein a sealed interface is defined between the base and the relief housing when the relief housing is in its first position, wherein the relief housing comprises an open vent aperture in fluid communication with the base cavity, and wherein the sealed interface is unsealed when the relief housing is in its second position to expose a relief vent aperture in the base.