You can use most types of electro capactitors with the Max232 chip, its just that the Tantalum ones have better performance - primarily their low leakage.
The downside is their cost in standard size components.
See Wiki for full details.
Yes..you can use eletrolytics with MAX232 which will work without problems. But for better stability and accuracy, tantalums are too prefered. It is not mandatory in any wayto use tantalums only. I have even used 104 disc capacitors which work well even today since 5-6 years. Cheers