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Thermal dust polarization is a powerful tool to probe magnetic fields($\textbf{B}$), grain magnetic properties, and grain sizes. However, asystematic study of the dependence of synthetic dust polarization on grainproperties in protostellar environments is not yet available. In this paper, wepost-process a non-ideal MHD simulation of a collapsing protostellar core withour updated POLARIS to study in detail the effects of grain magnetic propertiesand grain growth on dust polarization. We found that superparamagnetic (SPM)grains can produce high polarization degree $p \sim 10-40\%$ beyond $\sim 500$au because of their efficient magnetic alignment by magnetically enhancedRadiative Torque (MRAT) mechanism. The magnetic field tangling due toturbulence in the envelope causes the decrease of $p$ with emission intensity$I$ as $p\propto I^{\alpha}$ with the slope $\alpha \sim -0.3$. But within 500au, SPM grains tend to have weak internal alignment and be aligned with$\textbf{B}$ by RAdiative Torque mechanism only, producing lower $p \sim 1\%$and larger $\alpha \sim -0.6$. For paramagnetic (PM) grains, their inefficientmagnetic alignment produces $p << 1\%$, and the depolarization happens with asteep slope of $\alpha \sim -0.9$ owing to the alignment loss of large grainstoward the protostar. Grain growth can help to increase $p$ and weaken thedepolarization effect caused by turbulence beyond $500$ au for SPM grains. Butfor SPM grains within $\sim 500$ au and for PM grains, increasing $a_{\rm max}$enhances the depolarization effect due to the increasing amount of large grainswith inefficient alignment. Finally, we found that the polarization angledispersion function $S$ increases with increasing iron inclusions and $a_{\rmmax}$. Our findings reveal the dependence of magnetic field strength measuredusing the Davis-Chandrashekhar-Fermi technique on grain alignment degree.

Effects of Grain Magnetic Properties and Grain Growth on Synthetic Dust Polarization of MHD Simulations in Protostellar Environments