The cristallinity of the dispersed phase often decreases as the interface constrains the mobility of polymer chains. This effect is becoming more pronounced with decreasing particle size. So, in my opinion, it will be not easy to increase the crystallinity of dispersed phase. If applicable, you can try to use some nucleation agents, but this usually leads to faster crystalization and not to higher crystallinity.

Additional annealing at elevated temperature can theoreticaly help as well, but be aware that the morphology of the blend can change considerably especially in systems with higher amount of dispersed phase (cca 10 vol.%).

The question is too general. Different polymers have different crystal morphologies. Adding NA to the crystalline (dispersed) phase would obviously induce higher crystallization rate. Another option is to heating at or above crystallization temperature and quenching with liquid nitrogen. However, such treatment is largely influenced by the type of polymers.

As pointed out by others, Nucleating agent can be added. In addition or only heat treatment above crystallization temperature followed by very slow cooling can be tried.

thanks for all, I'll hang your suggestions into consideration on the preparation other samples.

Your question is too general. it will depond on

(i) the type de dispersed crystalline structure ( l like iPP  or PET, depending of the kintic of crystallization ( higher or slower).

(ii) the droplet size which can be influenced by the interfacial tension, the interface and interfacial area infuence the mobility of chains in crystalline structure

(iii) thermal treatment of the prepared blend if it is nexessary to do some annealing. you have to be carreful with morphology change ( but not worry at lower temperatures.

(iV) Orientation and it will depond on strain rate  of strechning, bi-strechning. This certainly change the crystal morphology.

you can try to use of course some nucleation agents. i was also shown in the literature some intersting effect of shear, pressure on the cristallisation behavior.