In:
No, Permanent Resident is not a Singaporean. Permanent Residency is not the status of Nationality but Immigration status.
Eg-1: If Permanent Resident is from India, then his nationality is Indian and not Singapore Permanent Resident. But his immigration status in Singapore is Permanent Resident.
Eg-2: If Permanent Resident is from Australia, then his nationality is Australian and not Singapore Permanent Resident. But his immigration status in Singapore is Permanent Resident.