PMMA (POLY METHYL METHACRYLATE) PREPARATION OF PMMA -:
PMMA is a transparent thermoplastic , used as a light weight or shatter-resistant alternative to glass.
PREPARATION OF PMMA-:
- Preparation of PMMA with high yield by room temperature suspension polymerization of methyl methacrylate(MMA)-:
To obtain the PMMA with high conversion methyl methacrylate(MMA) was polymerized in suspension using a room temperature initiator 2,2′-azobis(2,4-dimethylvaleronitrile) (ADMVN) . Suspension polymerization at 25 °C by adopting ADMVN proved to be successful in obtaining PMMA of high molecular weight (number-average degree of polymerization (Pn): 30,900–36,100) and of high yield (ultimate conversion of MMA into PMMA: 83–93 %) with diminishing heat generated during polymerization. The Pn and lightness were higher and polydispersity index was lower with PMMA polymerized at lower temperatures
II. Preparation of PMMA by high frequency ultrasound-:
Polymerization was carried out via free redicals from an aqueous solution of different concentration of a non-ionic Nonyl phenol etoxylade (NFE) or a cationic surfactant cetyltrimethylammonium bromide (CTAB) and different concentration of the insoluble monomer Methyl Metacrylate(MMA) as the disperse phase. The reaction was carried out at a frequency of 20 KHZ for 1 h under N2 atmosphere. The polymer articles obtained were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM).
III. Preperation of PMMA by suspension polymerization of Silver nano particle-:
To prepare high molecular weight PMMA/ silver microspheres , methyl methacrylate was suspension polymerized in the the presence of silver nano particle using a low temperature initiator at different condition The rate of conversion was increased with increasing initiator conversion . in case of adding silver nano particle , the rate of polymerization decreased slightly. High monomer conversion (about 95%) was obtained in the spite of low polymerization temperature of 30 °C . Under controlled conditions,PMMA/silver microspheres with various viscosity-average degree of
polymerization (6,000–37,000) were prepared.
IV. Preparation of PMMA by radical polymerization
The most common technique is the free radical polymerization of MMA. The free radical polymerization of acrylates and methacrylates is a chain polymerization across the double bond of the monomer. The free radical polymerization of MMA can be performed homogeneously, by bulk or solution polymerization, or heterogeneously, by suspension or emulsion polymerization. Free radical polymerization can be performed relatively easily. Unlike many types of polymerization absolute dryness is not necessary. In order for polymerization to proceed successfully, however, all oxygen must be removed from the polymerization. Oxygen is a radical scavenger, and terminates free radical polymerization.
QUESTION & ANSWER
- What do you mean by PMMA??
PMMA is poly( methyl metacrylate). PMMA is a transparent thermoplastic , used as a light weight or shatter-resistant alternative to glass.
2. What are the method used for the preparation of PMMA??
Mainly two process are used for the preparation of PMMA are
3. Is PMMA natural or synthetic??
PMMA is a synthetic material.
4. Why free radical polymerization is best technique for the preparation of PMMA??
Free radical polymerization can be performed relatively easily. Unlike many types of polymerization absolute dryness is not necessary.