The invention relates a process for the preparation of a bonded structure (4) comprising at least a first plastic part (1) having a first bonding surface (1a), said process comprising the step of a) treating at least part of a first bonding surface of said first plastic part with a flame of a propane-comprising gas, said propane-comprising gas being propane or a mixture comprising at least 50 wt. % of propane based on the weight of the propane-comprising gas with one or more gases selected from the group consisting of methane, ethane, butane, pentane, and hexane, wherein, during treatment with a flame of the propane-comprising gas, a flame is produced by burning a mixture of air and the propane-comprising gas, wherein the gas-to-air ratio is chosen such that the propane gas to oxygen volume ratio is equal to or less than 1:5.01, for example less than 1:5.00 and preferably at least 3.50 to obtain a first plastic part having a flame-treated first bonding surface.

A method for producing a component includes a) providing at least two preforms each made of a carbon composite material, b) joining the at least two preforms at least at one respective connecting surface to form a composite, in which a joining compound is introduced between the joining surfaces of the preforms and then cured and the joining compound contains silicon carbide and at least one polymer adhesive, and c) siliconizing the composite to form the component. A component, such as an optical component produced thereby, is also provided.

The present teachings contemplate a method comprising providing a first and second substrate, locating an initiator onto a surface of the first or second substrate, the initiator including a substance for initiating polymerization of a polymerizable adhesive, locating the polymerizable adhesive onto a surface of the first and second substrate, the adhesive including a monofunctional, difunctional, or multifunctional methylene malonate, or cyanoacrylate, and contacting first and second substrate.

A method of activating a surface of a plastics substrate formed from: (a) polyaryletherketone such as polyether ether ketone (PEEK) polyether ketone ketone (PEKK), polyether ketone (PEK); polyether ether ketone ketone (PEEKK); or polyether ketone ether ketone ketone (PEKEKK); (b) a polymer containing a phenyl group directly attached to a carbonyl group, for example polybutadiene terephthalate (PBT) optionally wherein the carbonyl group is part of an amide group, such as polyarylamide (PARA); (c) polyphenylene sulfide (PPS); or (d) polyetherimide (PEI); for subsequent bonding,
the method comprising the step of exposing the surface to actinic radiation wherein the actinic radiation: includes radiation with wavelength in the range from about 10 nm to about 1000 nm; the energy of the actinic radiation to which the surface is exposed is in the range from about 0.5 J/cm.sup.2 to about 300 J/cm.sup.2.

Hard to bond substrates are then more easily subsequently bonded for example using acrylic, epoxy or anaerobic adhesive.

A method for producing a component includes a) providing at least two preforms each made of a carbon composite material, b) joining the at least two preforms at least at one respective connecting surface to form a composite, in which a joining compound is introduced between the joining surfaces of the preforms and then cured and the joining compound contains silicon carbide and at least one polymer adhesive, and c) siliconizing the composite to form the component. A component, such as an optical component produced thereby, is also provided.

A method of activating a surface of a plastics substrate formed from: (a) polyaryletherketone such as polyether ether ketone (PEEK) polyether ketone ketone (PEKK), polyether ketone (PEK); polyether ether ketone ketone (PEEKK); or polyether ketone ether ketone ketone (PEKEKK); (b) a polymer containing a phenyl group directly attached to a carbonyl group, for example polybutadiene terephthalate (PBT) optionally wherein the carbonyl group is part of an amide group, such as polyarylamide (PARA); (c) polyphenylene sulfide (PPS); or (d) polyetherimide (PEI); for subsequent bonding, the method comprising the step of exposing the surface to actinic radiation wherein the actinic radiation: includes radiation with wavelength in the range from about 10 nm to about 1000 nm; the energy of the actinic radiation to which the surface is exposed is in the range from about 0.5 J/cm.sup.2 to about 300 J/cm.sup.2. Hard to bond substrates are then more easily subsequently bonded for example using acrylic, epoxy or anaerobic adhesive.

The present teachings contemplate a method comprising providing a first and second substrate, locating an initiator onto a surface of the first or second substrate, the initiator including a substance for initiating polymerization of a polymerizable adhesive, locating the polymerizable adhesive onto a surface of the first and second substrate, the adhesive including a monofunctional, difunctional, or multifunctional methylene malonate, or cyanoacrylate, and contacting first and second substrate.