Use of thermal analysis techniques for examining blow-molded pet bottle specimens

Wingard, Charles D.

doi:10.1007/bf01987461

Cited by 5 publications

(4 citation statements)

References 5 publications

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“…T g measurements of PET using differential scanning calorimetry (DSC) gave different values. 7,10,19,20 The glass transition of PET was found to linearly decrease with the increase of crystallinity. 20 However, dynamic mechanical analysis (DMA) 21 on PET ®lms showed an increase in T g with increasing crystallinity.…”

Section: Resultsmentioning

confidence: 94%

Thermally stimulated current studies on molecular relaxation and blow moulding of poly(ethylene terephthalate)

Satoto¹,

Morikawa²,

Hashimoto³

1999

Polym. Int.

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The thermally stimulated current (TSC) technique has been used to investigate molecular relaxation in poly(ethylene terephthalate) (PET) films unstretched and biaxially stretched at 90 and 95 °C. Unstretched PET films show two peaks at 77 and 90 °C corresponding to α and ρ relaxation processes, respectively. The α relaxation is associated with the main glass transition of the material. The ρ peak with lower intensity is attributable to permanent dipoles. Both biaxially stretched samples show one TSC peak at 95 °C, supposed to correspond to ρ relaxation. The disappearance of the α peak, accompanied by the displacement of the ρ peak to higher temperature, is the result of the higher thermal stability of the permanent dipoles, which is strongly influenced by the stiffening of amorphous parts and the crystallization by stretching. In both stretched samples, the continuous distribution of pre‐exponential factors over activation energies observed might correspond to a single relaxation mode. The kinematics of stretching PET has been discussed in terms of activation energy and temperature dependence of relaxation time. © 1999 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 94%

Thermally stimulated current studies on molecular relaxation and blow moulding of poly(ethylene terephthalate)

Satoto¹,

Morikawa²,

Hashimoto³

1999

Polym. Int.

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“…Besides, the possibility of applying load to the sample allows this technique to be used to assess some important properties, such as the glass transition, melting temperatures, stress relief effects at glass transition, coefficients of thermal expansion (CTE), etc. [23,24].…”

Section: Dsc and Tmamentioning

confidence: 99%

“…However, TMA is an important technique in the field of thermal analysis, which allows the evaluation of the dimensional properties of a sample during heating or cooling, or even under isothermal conditions. Besides, the possibility of applying load to the sample allows this technique to be used to assess some important properties, such as the glass transition, melting temperatures, stress relief effects at glass transition, coefficients of thermal expansion (CTE), etc., [23,24].…”

Section: Dsc and Tmamentioning

confidence: 99%

Accelerated Aging Ultraviolet of a PET Nonwoven Geotextile and Thermoanalytical Evaluation

et al. 2022

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Nonwoven geotextiles are geosynthetic products that are highly susceptible to ultraviolet degradation because light can reach a large area of the material due to its fiber arrangement. Even with additives, which delay the degradation process, material decomposition still occurs, and therefore the product’s long-term durability can be affected. In this paper, the mechanical and thermal behavior of a commercial nonwoven polyester geotextile subjected to accelerated ultraviolet aging tests were evaluated. The deterioration was evaluated by comparing the physical properties (mass per unit area, thickness, and tensile strength) and thermal behavior (thermogravimetry—TG, thermomechanical analysis—TMA, and differential scanning calorimetry—DSC) before and after exposure times of 500 h and 1000 h. The results showed that the ultraviolet aging tests induced some damage in the polyester fibers, leading to the deterioration of their tensile strength. For 1000 h of exposure, in which the reduction was larger, scanning electron microscopy (SEM) found some superficial disruption of the fibers, indicative of damage. TG and DSC could not capture the effects of UV radiation on polymer degradation, unlike TMA. This latter technique was effective in showing the differences between specimens before and after UV exposure.

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“…- Cutting out a sample from the bottle and subjecting it to a dynamic mechanical analysis (DMA) or thermal mechanical analysis (TMA) or using a shrinkage dilatometer [41][42][43][44].…”

Section: Influence Of Deformation and Temperature On The Thermal Resistance Of Pet Materialsmentioning

confidence: 99%

A literature survey of the influence of preform reheating and stretch blow molding with hot mold process parameters on the properties of PET containers. Part II

Wawrzyniak¹,

Karaszewski²

2020

Polimery

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The paper presents a wide analysis of the literature on the modified blow molding process with simultaneous stretching of PET [poly(ethylene terephthalate)] material for storing hot filled drinks. The paper is a continuation of the first part presented earlier [1]. In this part it is presented in detail the impact of stretch blow molding with hot mold process parameters on thermal resistance of PET containers. An analysis of the literature shows that the relaxation of the amorphous phase has the greatest impact on the thermal stability and pressure resistance of the bottle. At the same time, the thermal stability of the bottle increases, and the pressure strength decreases when the relaxation of the amorphous phase is increased, and the crystallites increase to the largest size possible without causing thermal whitening of the material. The measure of relaxation of the amorphous phase is based on the amount of oriented and "rigid" amorphous phase, since the higher the degree of relaxation of the amorphous phase, the smaller the amounts of oriented and rigid amorphous phase. The main parameters of the hot mold SBM process that affect the properties of the hot filling bottle are the intrinsic viscosity of the preform material, the power profile of the heating lamps in the heating oven (there are seven levels of heating lamps), the heating time in the oven and the associated time of temperature-induced crystallization prior to the SBM process, the speed of the stretching rod, the pre-blow delay due to the stretching rod position, the pre-blow pressure, pre-blow duration, air blow pressure, duration of the main blow, temperature profile of the heated blow mold (there are two heat zones for the blow mold, the lateral surface of the bottles and base zone), duration of annealing in the mold, cooling air temperature of a bottle in a blow mold fed by a stretching rod, and the pressure in the feed branch for air cooling of a bottle in a blow mold fed by a stretching rod. Thus, the properties of a bottle or hot fill can be influenced by as many as 20 factors during the SBM process with a hot mold.

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Use of thermal analysis techniques for examining blow-molded pet bottle specimens

Cited by 5 publications

References 5 publications

Thermally stimulated current studies on molecular relaxation and blow moulding of poly(ethylene terephthalate)

Thermally stimulated current studies on molecular relaxation and blow moulding of poly(ethylene terephthalate)

Accelerated Aging Ultraviolet of a PET Nonwoven Geotextile and Thermoanalytical Evaluation

A literature survey of the influence of preform reheating and stretch blow molding with hot mold process parameters on the properties of PET containers. Part II

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