# Emulsion Polymerization of Tung Oil-Based Latexes with Asolectin as a Biorenewable Surfactant
## 3 Results and Discussion  
In order to verify that tung oil/asolectin-based emulsions can be polymerized under free radical conditions in the presence of DTBP, 1:4 (xylene:water) by weight emulsions of various ratios of tung oil and asolectin were cured in a convection oven at 100 \({}^{\circ}\)C for 24 h. The 1:4 (xylene:water) by weight solvent ratio was determined based on related literature [20] and after a major screening of solvent combinations. As described previously, the polymerized emulsions were dried in a vacuum oven at 60 \({}^{\circ}\)C for 24 h and the dried materials recovered were subjected to Maldi-TOF analysis. Figure 2 shows the Maldi-TOF spectrum of the dry products from the emulsion containing a 1:1 weight ratio of tung oil and asolectin. Two major signals can be clearly seen in the 11,000-12,000 m/z range in Figure 2, confirming the formation of high molecular weight products upon cure of the emulsion. Despite the promising results shown in Figure 2, the dry products obtained from tung oil and asolectin were exceedingly soft, rubbery, and tacky. In order to enhance the mechanical characteristics of the dry film, as demonstrated previously with related bio-based polyolefin systems [1], it became necessary to incorporate other reactive olefins, such as DVB and BMA. Upon addition of more reactive components, a natural increase of the dry products' crosslink density made it impossible to obtain clear Maldi-TOF spectra due to the inherent difficulty of analyzing thermoset materials through this technique. Previously, the bulk free radical polymerization of 40 wt.% of tung oil, 30 wt.% of BMA, 20 wt.% of DVB, and 10 wt.% of asolectin had been successfully achieved after heating the crude resin in the presence of DTBP at 140 \({}^{\circ}\)C for 2 h and 50 min [13]. The same resin composition was therefore prepared into a xylene/water emulsion as described in the _Experimental_ section. Xylene was chosen as the most appropriate solvent due to its compatibility with the monomers and also due to  
Figure 2: Maldi-TOF spectrum of dried products from a xylene/water emulsion containing a 1:1 weight ratio of tung oil and asolectin subjected to 24 h heating at 100 \({}^{\circ}\)C in the presence of di-_tert_-butyl peroxide (DTBP). its relatively high boiling point, allowing for higher polymerization temperatures. Water has a lower boiling point than xylene, and therefore, the highest temperature at which the system can be cured is 100 \({}^{\circ}\)C. A weight ratio of 1:4 (xylene:water) was found to create a stable emulsion after 20 min of sonication. In order to select the optimum resin/solvent ratio, emulsions containing overall monomer weights of 200 mg, 400 mg, and 600 mg were prepared, as shown in Figure 3.  
It is obvious from Figure 3 that an immediate phase separation occurs for samples containing 400 mg (Figure 3B) and 600 mg (Figure 3C) of total monomer weight, while a total monomer weight of 200 mg (Figure 3A) produced no phase separation and therefore appeared to create a stable emulsion. The latter composition was observed over a period of 30 min in order to assess the stability of the emulsion formed. The results can be seen in Figure 4.  
From the pictures in Figure 4, the emulsion containing 200 mg of total monomer weight doesn't change its appearance for at least 30 min after preparation. It is therefore hypothesized that, if the free radical polymerization reaction starts within the first 30 min following the preparation of the emulsion, the monomers present in the non-polar micelles will start crosslinking before disruption of the emulsion, leading to spherical particles. The emulsions prepared held their stability for an extended period of time when kept in a closed container. No phase separation was observed since the emulsion preparation. The progress of the polymerization of the monomers at the cure temperature employed was monitored through dielectric analysis (DEA).