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OwnerWon-Seok Lyoo, Han-Do Ghim +5inventors
InventorsWon-Seok Lyoo, Han-Do Ghim, Jeong-Hyun Yeum, Chan-Shik Park, Wong-Jae Yoon, Tae-Hwan Noh, Dong-Yoon Shin
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Poly(vinyl pivalate) exhibiting a high syndiotacticity and a high molecular weight is prepared through suspension polymerization of vinyl pivalate at low temperatures. Furthermore, poly(vinyl pivalate) microspheres with a high syndiotacticity is prepared for use as a precursor for PVA with a high molecular weight and a high syndiotacticity through suspension polymerization of vinyl pivalate at 20 to 70° C. with the use of azobisdimethylvaleronitrile as an initiator. In addition, poly(vinyl pivalate) is separated using a dispersing agent and a precipitating agent to thereby prepare poly(vinyl pivalate) microspheres with various sizes and a uniform size distribution. The poly(vinyl pivalate) microspheres are suspended in an aqueous alkali soloution such that only the surface thereof is saponified to PVA. In this way, embolic particles with a spherical shape are obtained to be useable as an embolic material for embolotherapy.
A method of preparing poly(vinyl pivalate) microspheres having uniform particle diameters ranging from 1 μm to 3000 μm, where a difference between upper and lower limits of the particle diameters ranges from about 1 μm to about 500 μm, and a polydispersity index of particle diameter ranging from 1.00 to 1.60, the method comprising:
Embolic particles having a dual structure of an outer PVA skin and an inner poly(vinyl pivalate) core where a degree of saponification of the poly(vinyl pivalate) is in the range of 1 to 99.9%, the embolic particles having uniform particle diameters ranging from 1 μm to 3000 μm, where a difference between upper and lower limits of the particle diameters ranges from about 1 μm to about 500 μm, and a polydispersity index of particle diameter ranges from 1.00 to 1.20.
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