گیتی میرمحمدصادقی

Ethylene Carbonate (EC) was selected as a new solvent in order to establish a rapid liquefaction technique converting lignocellulosic waste into useful chemicals. Beechwood sawdust was liquefied by using Ethylene Carbonate (EC) as a solvent and sulfuric acid as a catalyst at high temperatures (110-160°C) and at three times (20, 40, 60 minutes) for the preparation of suitable polyol. After the liquefaction process at different temperatures and times and investigation of characterization of hydroxyl number, acid number, and yield of polyol were seen that the temperature of 130°C was an appropriate temperature for the production of polyol. Then in order to determine the appropriate time for producing the polyol at this temperature, the liquefaction process was continued at different times (40, 60, 90, 120, and 180 min) which as a result 120 minutes being selected as an appropriate time for the preparation of polyol. Also, the results showed that with increasing the temperature and time of liquefaction, the acid number and yield, and viscosity were increased, but hydroxyl number was reduced. The FTIR spectroscopy analysis showed the existence of the hydroxyl groups (OH) in the liquefied Beech sawdust (polyol) and confirmed that wood sawdust is a source of bio polyols. Also, it can be concluded that bio polyol is suitable for the preparation of polymeric products, including polyurethane adhesive. Statistical analysis showed that variation of hydroxyl and acid number, yield, and viscosity have a significant difference with increasing at temperature and time.

Identification of macrofouling is the first step in their controlling on existing structures in the seas. During the four sampling phases from June 2015 to September 2016, eight species/genus belonging to 8 macrofouling families were identified and classified from the fish cages of Bandar Lengeh. Water physico-chemical parameters including temperature, salinity, dissolved oxygen and pH were measured in all seasons, and RDA test was used to assess biodiversity. The dominant macrofouling in this study was Amphibalanus sp. which was observed in all seasons. The highest mean biomass in macrofoulings belonged to Perophora sp.  with a mean weight of 214.39 ± 62.4 gr/cm2 in autumn. Significant differences were observed between the mean weight of macrofoulings in different seasons and also between mean water factors in four seasons (p<0.05). There was a significant difference between the mean water parameters in the four seasons (p<0.05). The results of RDA and Pearson correlation tests showed that temperature and oxygen were two environmental parameters affecting the diversity and biomass of cages biofouling in Bandar Lengeh.

Although there are many works published on shape memory polyurethanes,but no report is found on PCL-based polyurethane composite using PCLwith molecular weight of 2000 g/mol and nanoclay particles via in-situ polymerization. In this work, we try to approach some problems concerning the chemical structure, dispersion of nanoparticles in the matrix and interaction between nanoparticles and polymer in shape memory of PCL (Mn= 2000 g/mol)-based polyurethane/nanoclay composites. While PCL (Mn= 2000 g/mol) polyurethane constituted the soft segments, MDI/BD formed the hard segments. The weight ratio of soft to hard segments was found to be 65/35. Composites were synthesized in presence 1 and 3 wt% of nanoclay (Cloisite®30B) via in-situ polymerization by a twostep method. Effect of nano particles on their interactions with polyurethane chains,crystallinity, mechanical properties and shape memory have been investigated using FTIR, DSC, tensile test and shape memory analysis, respectively. Phase mixing and hydrogen bonding intensified with 1 wt% nanoclay particles, whereas 3 wt% nanoclay led to phase separation. XRD, MTDSC, AFM analyses showed exfoliation of samples with 1 wt% nanoclay in the matrix and better tensile strength in comparison with pure sample and higher shape recovery compared to all other samples. Crystallinity of soft segments resulted in higher modulus and improvement of shape memory. TGA results showed a three-step degradation mechanism for PCL, MDI and BDO-based polyurethane.