Abstract: A method of moulding foamed synthetic resin pellets of polyolefine in a mould, wherein the synthetic resin pellets are prepared with volumne of closed cells being more than 65 % of the total volume of the total cells and having an inorganic gas in the cells at a pressure higher than 1.18 atmospheres, then filled in a mould which is not completely gas tight, and then heated to expand and tightly adhere to each other. The pressure in the mould can be lower than ordinary pressure or at a vacuum and the pressure of the resin can be at a pressure higher than ordinary pressure. The moulded product may be removed from the mould after cooling or during cooling when the inner temperature of the product is between its melting point and a temperature 50.degree.C below the melting point. The obtained product may be stored at a temperature of 30.degree. to 70.degree.C below the melting point.

Abstract: A process for preparing a polyalkylene oxide having allyl end-group, by subjecting an alkylene oxide monomer to addition polymerization in the presence of potassium hydroxide in an amount of 2 to 30% by mole to the monomer at a temperature of 20.degree. to 100.degree.C., and reacting the polymerized alkylene oxide with an allyl halide compound, or by subjecting the monomer to addition polymerization in the presence of potassium hydroxide, reacting the polymerized alkylene oxide with an organic polyhalide and then reacting with an allyl halide compound. Potassium hydroxide is preferably employed in combination with the specific initiator. There can be prepared polyalkylene oxide of which all of the chain ends are substantially allyl group.