NOVELTY - Thermoplastic compound (I) comprising polyhydroxyalkanoate and an amount of surface treated precipitated calcium carbonate to crystallize the polyhydroxyalkanoate at a temperature of more than 108 degrees C, is new.    USE - (I) Are useful for making an article, which is in the form of computer chip mounts, fuel cell radiators, aircraft leading edges, bipolar plates for fuel cells, computer enclosures, electrodes, automobile interiors, building interiors, medical instruments, radioactive containers, radiation dosimeters and detection equipment (all claimed), and extruded or molded plastic articles. (I) Are also useful in plastic articles in the following industries, which are appliance (refrigerators, freezers, washers, dryers, toasters, blenders, vacuum cleaners, coffee makers and mixers), building and construction (fences, decks and rails, floors, floor covering, pipes and fittings, siding, trim, windows, doors, molding and wall coverings), consumer (power hand tools, rakes, shovels, lawn mowers, shoes, boots, golf clubs, fishing poles and watercraft), electrical/electronic (printers, computers, business equipment, liquid crystal display projectors, mobile phones, connectors, chip trays, circuit breakers and plugs), healthcare (wheelchairs, beds, testing equipment, analyzers, labware, ostomy, infusion sets, wound care, drug delivery, inhalers and packaging), industrial (containers, bottles, drums, material handling, gears, bearings, gaskets and seals, valves, wind turbines and safety equipment), packaging (food and beverage, cosmetic, detergents and cleaners, personal care, pharmaceutical and wellness), transportation (automotive aftermarket parts, bumpers, window seals, instrument panels, consoles, under hood electrical and engine covers) and wire and cable (cars and trucks, airplanes, aerospace, construction, military, telecommunication, utility power, alternative energy and electronics).    ADVANTAGE - (I), with nucleation by the surface treated precipitated calcium carbonate resist crystallinity creep at a much lower expense than using boron nitride for that purpose. (I): has a crystallization temperature of more than 108 degrees C; and is thermally decompostable.