Three  soil  profiles developed on  Olivine  basalt,  located  in   three  villages in Ikom area  of south­ eastern Nigeria  were  studied, described and  characterised for  the  purpose of  appraising their suitability for cultivation of rubber (Hevea   brasiliensis)   in  that   ecological   zone.    The  minera­ logy of clay fraction of these soils was also  investigated using  transmission electron  microscope (TEM) and  X-ray  diffractometer (XRD). 
The  soils  were generally  deep,  moist  and  heavy-textured, with  clay  content varying from  30 to 70 per cent. Silt (2-20 µm) content varied from 14 to 43 per cent.     In spite of the clayey texture, the soils were well-drained.   All the soils were  strongly   acidic,   w1th moderate to   high levels  of soluble  AI, moderate to  base  saturation and   low ECEC.   Exchangeable Ca,  K and  organic  C were,   however,   appreciably  high in  the surface horizons.

The soils had a kaolinitic clay mineralogy but there were substantial amounts of goethite, hematite, quartz and   little smectite.   The  soils  were  appraised  to  be   suitable for   rubber  cultivation on  the  basis  of  the  prevailing agro-climatic conditions,   excellent  physical  properties (texture, structure, drainage and   rooting volume)  and  some  chemical properties, mainly   high  organic matter, exchangeable Ca and  K status.

Light  and  scanning  electron  microscopic (SEM)  studies on  pollen  morphology of three  Hevea species namely, H. brasiliensis (Willd. ex Adr. de Juss.)  Muell. Arg.,  H. spruceana Muell. Arg. and of  H. benthamiana Muell.  Arg.  were carried   out.    The    pollen   grains  of  Hevea are   3-zono­ colporate and  there  are  significant  differences  among   the  species  with  regard  to  size,   exine thickness  and   pore  diameter. SEM  studies  offer  new  useful  information on  the   taxonomy of  Hevea.

The  use of 1, 2-polybutadiene (1, 2-PB) as a substitute  for styrene-butadiene rubber (SBR)-high styrene resin in conventional  microcellular  (M.C) sole compounds was  studied.   Effects of concentration  of 1,2-PB,  filler combinations  and  concentration  of blowing agent on   technical properties of microcellular soles prepared  from  blends of natural  rubber(NR) and  1,2-PB are discussed.   Cell characteristics of  seven  selected  vulcanizates  were studied  using a scanning electron microscope (SEM).    It was found  that blending of  1,2-PB with  NR results  in higher expansion, lightness, higher flex life and lower blooming in M. C  soles.    However, other technical properties are slightly inferior to those of M.C  soles prepared using SBR-high styrene resin.   A combination  of china clay, precipitated silica and aluminium silicate in the  ratio 60 : 30 : 15 is found  to  be an acceptable  filler combination  for  NR/1,2-PB  based  M. C soles.

The distribution and  proportion of tension and  normal  wood,  the dimensional variations of wood fibres with emphasis on positional effect and  their   variation from   tree  to  tree   were  studied  in clone PB 86 of Hevea brasiliensis.    The formation of tension wood was  associated with growth eccentricity.   The  proportion of tension  wood  increased with the increase  in  sampling height. The tension wood  fibres (gelatinous fibres)  were short   and  broad  as  compared to   the   normal wood  fibres.    The average  fibre length  showed  significant  difference  among various height levels of  the  tree  trunk.

Studies on  rheological and  die swell behaviour  of  natural  rubber  melts were carried  out  in a Davenport Capillary Rheometer.    Two types of rubber, a Standard  Malaysian Rubber  (SMR-L) and a viscosity stabilised form of SMR (SMR CV-70) were masticated in a  two-roll mill at 50°C for different time intervals.    The extent of mastication is expressed as plasticity, measured from Wallace rapid  plastimeter. Both type of rubbers have shown pseudoplastic behaviour  With the value  of  non-Newtonian  index,  n, varying between 0.1675 and 0.2695 under different levels of mastication.    Die swell increases with plasticity and shear stress, but decreases with increasing levels of mastication.The value of non-Newtonian  index first decreases  with  plasticity and then increases.   The apparent viscosity is found  to decrease with the rate of shear and the extent of mastication. It is also established that the  power-law model describes the behaviour of both masticated and unmasticated rubber.

Thermoplastic elastomers prepared by melt mixing  of isotactic-polypropylene(PP)and natural rubber (NR)   were  evaluated for  abrasion  resistance.   The  morphology of the blends  and  the patterns developed   on  the  abraded surfaces  of  the  test  samples  were studied using a scanning electron  microscope. The morphology of the blends  was found to change from  that of a dispersed phase  of  natural rubber   to  that  of a continuous phase  when  the  NR : PP  ratio  was  changed from  30 :70 to 60 :40 .  Correspondingly, a change  in the mode of abrasion of the  blends from abrasive  type  with horizontal groove  patterns to frictional type  with  vertical  ridge  patterns on the abraded surface  was observed  for  these  blends. This change in the pattern of abrasion was prominent in dynamically crosslinked blends  compared  with  the  uncrosslinked ones.