ALEXIS AKWAGYIRAM and CHIJIOKE OHUOCHA AS women in hairnets and anti-coronavirus masks sort through folded nappies coming off a conveyor belt, the head of the Nigerian firm they work for wonders how much longer he can afford to keep them in employment. Around 80% of the materials that go into Lagos-based diaper and sanitary towel manufacturer Wemy's products are imported. To buy them, Paul Odunaiya needs dollars, which he can no longer find. "We're pleading with our suppliers to wait a bit longer so that we can source dollars and pay them," Odunaiya told Reuters. With the price of oil,…