La concentration en groupe imide de la résine précurseur de polyimide après imidation est de 28,0 %-33,0 %.
The imide group concentration of the , polyimide precursor resin, after imidization is 28.0%-33.0%
https://context.reverso.net/translation/french-english/précu...

L'invention porte sur une résine précurseur de polybenzoxazole, dans laquelle la quantité d'impuretés ioniques qui y est contenue est réduite
https://patents.google.com/patent/WO2011152063A1/fr
Provided are a polybenzoxazole precursor resin in which the amount of ionic impurities contained therein is reduced …
https://patents.google.com/patent/WO2011152063A1/en

L'invention concerne un procédé de fabrication d'une pièce en matériau composite comprenant un renfort fibreux densifié par une matrice, … contenant un précurseur d'une matière consolidante et transformation (S7),
https://patents.google.com/patent/WO2008050068A2/fr
The invention relates to a process for manufacturing a part made of a composite comprising a fibrous reinforcement densified by a matrix … containing a precursor of a consolidating material and transformation (S7)
https://patents.google.com/patent/WO2008050068A2/en

… à l’aide d’une résine précurseur de carbone ou céramique
…. using a carbon or ceramic precursor resin
https://www.researchgate.net/publication/329355140_Synthese_...

ou une résine précurseur de matrice, par exemple précurseur de carbone C ou de carbure de silicium SiC."
=>
or a precursor (of) matrix resin, for example precursor of carbonate C or silicon carbide SiC. "

What is the « matrix »:

A thermoset polymer matrix is a synthetic polymer reinforcement first developed for structural applications,[1] such as glass-reinforced plastic radar domes on aircraft and graphite-epoxy payload bay doors on the space shuttle. In polymer matrix composites, polymers act as binder or matrix to secure in place incorporated particulates, fibres or other reinforcements.
https://en.wikipedia.org/wiki/Thermoset_polymer_matrix

A polymer matrix composite (PMC) is a composite material composed of a variety of short or continuous fibers bound together by an organic polymer matrix.
:
In addition to applications as ceramic matrix composite precursors, silicone resins in the form of polysiloxane polymers made from silicone resins with pendant acrylate, vinyl ether or epoxy functionality find application as UV, electron beam and thermoset polymer matrix composites where they are characterised by their resistance to oxidation, heat and ultraviolet degradation.
https://en.wikipedia.org/wiki/Polymer_matrix_composite

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Note added at 12 hrs (2019-06-03 13:33:25 GMT)
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What about?

5% allyl-AHPCS + 10 vol% SiC serves as a precursor matrix resin for the preparation of C/SiC composite without using any interfacial coating onto the reinforcement.
https://www.researchgate.net/publication/248280586_Allylhydr...

Particularly in the case of unsaturated precursor matrix resin, it is commonplace to also include an unsaturated reactive diluent as a matrix component prior to curing.
http://patents.com/us-9365685.html

[0003] Ceramic composites are useful for many applications for their hardness and ability to withstand high heat. Ceramic composites are formed by first combining a fibrous reinforcement material and, optionally, a particulate filler material with a ceramic precursor matrix resin of relatively low viscosity.
http://www.freepatentsonline.com/y2002/0190409.html

Candidate fibers were analyzed by determining the effect of exposure to pyrolysis gases evolved by candidate matrix resins, and by comparing fiber strain-to-failure with pyrolyzed matrix strain-to-failure. Candidate fibers and a slug of precursor matrix resin were inserted into graphite tubes fitted with tight end caps.
https://archive.org/stream/DTIC_ADA303841/DTIC_ADA303841_djv...