A Portugese cork grip can be mounted onto the handlebar with a pu wood adhesive fiber glue. 

To do so you keep the grip in oblique position and apply the glue while slowly turning the grip. After this you gently screw the grip onto the handlebar, so that the glue distributes well. The vibrant glue starts to fizz a bit and hardens, which results in a fixed connection. 

The recommended drying time is 24 hours.