Final answer:
Blow molding and rotational molding are processes limited to thermoplastic polymers because they can be reformed when heated, unlike other methods like compression molding and sintering.
Step-by-step explanation:
The processes that are generally limited to thermoplastic polymers are blow molding and rotational molding. These processes utilize the ability of thermoplastics to soften when heated and be reformed upon cooling.
Compression molding can also be used for thermoplastics but is not as exclusive as the other two methods because it can be used for some thermosetting plastics as well, albeit the process is more complicated for thermosets as it involves the polymerization within the mold. Sintering, on the other hand, is a process typically used with metals and ceramics, and not limited to just thermoplastics.