Name	Monomer Unit	Stability in CSA	Soluble in CSA	Ref.
Poly (arylene ether sulfone)–PASS-4		>150 days at RT	Yes	[123]
Poly (arylene ether sulfone)		>150 days at RT	No	[123]
Polypropylene		Stable at RT, oxidized at >100 °C	No	[124]
Kevlar(poly(p-phenylene terephthalamide)		>3 months at RT	Yes	[58]
Polyaniline		Stable for at least a few weeks at RT	Yes	[125]
Polyimide V		Stable for at least a few days at RT	Yes	[126]
Polyimide VI		Stable for at least a few days at RT	Yes	[126]
Polyimide VIII		Stable for at least a few days at RT	No	[126]
Polyimide IVa		Stable for at least a few days at RT	Yes	[127]
Polyethersulfones		A few weeks at RT in CSA (Sulfonated in oleum at 30 °C)	Yes	[128,129]
Poly(phthalazinones)poly(phthalazinone-ether ketone) (PPEK)		>95 h at RT (sulfonated in oleum at 23 °C)	Yes	[130]
Poly(phthalazinone ether sulfone) (PPES)		Half-life to sulfonation ~50 h at 25 °C	Yes	[130]
Polyarylhydrazides		A few weeks at RT	Yes	[131]
Polyarylhydrazides		Rapidly hydrolyzed	N/A	[132]
Poly-Schiff’s bases		A few weeks at RT	Slightly soluble	[133]
Poly-Schiff’s bases		A few weeks at RT	Yes	[133]
Silicon polyamide		Stable (gave red solutions, suggesting ring protonation, i.e., long-term liability to reaction)	Yes	[134]
		Stable (gave red solutions, suggesting ring protonation, i.e., long-term liability to reaction)	Yes	[134]
Nylon 6 (e-caprolactam polymer)(also Nylon 2, 12)		At least a few days at RT (viscosity is measured in 96% H2SO4)	Yes	[56,57]
		At least a few days at RT	Yes	[59]
		At least a few days at RT	No	[59]
Quinoxaline ladder polymers		At least a few days at RT	No	[135]
Polyglycine		Limited hydrolysis on hour timescale in cold H2SO4	N/A	[54,55]
PEEK		50% sulfonated in 96.3% sulfuric acid at 22 °C after hours	Yes	[53]
Polystyrene		Fully sulfonated in minutes at 90 °C, 50% after 10 h at 70 °C, implies stable at RT.	Unknown	[136]
Polystyrene sulfonate		Stable for >100 h at 90 °C	Yes	[136]