Advances in Chemical Engineering and Science, 2012, 2, 435-443 http://dx.doi.org/10.4236/aces.2012.24053 Published Online October 2012 (http://www.SciRP.org/journal/aces) Effects of Side-Chain on Conformational Characteristics of Poly(3,5-Dimethyl-Phenyl-Acrylate) in Toluene at 40˚C Nasrollah Hamidi 1* , Stanley Ihekweazu 2 , Christopher A. Wiredu 3 , Onize H. Isa 4 , Kevin Watley 4 , Christopher Rowe 3 , Briante’ Nimmons 3 , Alexis Prezzy 4,5 , Shane Scoville 4 , Quentin Hills 4,5 , Judith Salley 1 1 Department of Biological and Physical Sciences, South Carolina State University, Orangeburg, SC, USA 2 Department of Civil and Mechanical Engineering Technology, South Carolina State University, Orangeburg, SC, USA 3 North High School, North, SC, USA 4 Orangeburg Wilkinson High School, Orangeburg, SC, USA 5 Claflin University, Orangeburg, SC, USA Email: * Nhamidi@scsu.edu Received August 11, 2012; revised September 13, 2012; accepted September 22, 2012 ABSTRACT The intrinsic viscosity [η] of poly(3,5-dimethyl-phenyl-acrylate) (35PDMPA) solutions were evaluated throughout the measurements of the flow times of toluene and polymer solutions by classical Huggins, and Kraemer’s methods using a Cannon-Ubbelohde semi-micro-dilution capillary viscometer in a Cannon thermostated water bath at 40˚C ± 0.02˚C. The values of Huggins’ constant estimated ranged from 0.2 to 0.4 which were within expectations. The intrinsic viscosities and molecular weight relationship was established with the two-parameter classical models of Staudinger-Mark-Houwink- Sakurada and Stockmayer-Fixman. Conformational parameter C ∞ and σ indicated 35PDMPA be semi flexible. Also, the rigidity of 35PDMPA was confirmed by Yamakawa-Fuji wormlike theory modified by Bohdanecký. The molecular parameters were estimated and compared. The results showed that 35PDMPA behaves like a semi-rigid polymer in toluene at 40˚C rather than a random coil flexible macromolecule. Keywords: Intrinsic Viscosity; Poly(3,5-Dimethyl-Phenyl-Acrylate); Conformational Parameters; Rigidity Factor; Kuhn Statistical Length 1. Introduction The influence of temperature and side chain groups on the physical properties of polyethylene chains is well documented [1]. In the case of polyacrylates, interests have focused on the changes induced by altering the length of alkyl ester group [2] or identity of the ester linkage such as phenyl with alkyl substituent in various positions [3]. One way to evaluate and analyze the prop- erties of such polymers is at least to correlate the depend- ence of their equilibrium configuration to their structure. Among the methods of evaluating configurational prop- erties are the application of matrix methods in the form of rotational isomeric state (RIS) model to calculate conformational properties such as Flory’s characteristic ratio (C ∞ ) [4] and or application of the wormlike model based on Yamakawa-Fujiitheory [5] and its simplified form byBohdanecký [6]. Neither the RIS nor the worm- like model has been applied to evaluate the influence of side chain on unperturbed dimensions of 35PDMPA. This paper presents experimental findings pertaining to dilute solution properties of 35PDMPA in toluene at 40˚C. The intrinsic viscosity of a macromolecule in a dilute solution is a measure of its hydrodynamic average size, form, and shape in the solution. Many studies were found that explored the empirical relationships between coil dimensions of synthetic polymers with their intrinsic viscosity [1-7]. The most frequently used relationship between intrinsic viscosity, [η], and the weight-average molecularmass, M w , is the Mark-Houwink-Kuhn-Saku- rada (MH) Equation:   w  K M ; (1)    where, the parameter α is a measure of the thermody- namic power of solvent and K α is a measure of coil vol- ume for an unperturbed condition or ideal solvent called θ-condition for random coil polymers. Numerous re- searchers [1-8] have demonstrated the validity of the MH equation applied to random coiled polymers for molecu- lar weights ranging in several orders of magnitude. By increasing thermodynamic strengths of solvents, the magnitude of coefficient α would increase while the magnitude of K α would decrease. Generally, for the ran- * Corresponding author. Copyright © 2012 SciRes. ACES