Are all glue sticks PVA-based? How to find out?
Not all glue sticks work! The working ingredient of a glue stick is Polyvinylpyrrolidone; a more elaborate answer is found here on question: &quot;Why does hairspray work as an adhesive for ABS?&quot;.
There are very good alternatives to glue sticks and hair spray nowadays. Specific adhesion sprays exist for several years now (e.g. Dimafix, 3DLAC, Magigoo for PA, Plasticz, PrintaFix, Dr.Mat, etc.; my personal experience is with the first 2 mentioned, both work for nylon: Dimafix has more tack at higher temperatures &gt; 80 °C, up to 80 °C 3DLAC works perfect).
E.g. Dimafix has a higher temperature application range than e.g. 3DLAC. From the manufacturer can be seen that:

Source: http://www.dima3d.com/en/home/dimafix/
This image shows that the spray has its maximum tack/adhesion at about 120 °C and holds this adhesion level at least up to about 145 °C according to the image.
However, not all glues get stronger with temperature! PVA (also called PVAc) glues soften very quickly, making them good only at low temperature. See &quot;Influence of temperature on the strength of bonded joints&quot; which discloses this graph for PVAc Rhenocoll 3W, 4B Plus: