- 1 Introduction To Virgin and Recycled Polyester
- 2 Saturation Of Dye On Fabric
- 3 Conclusion
Polyester is made from petroleum resource that creates damaging environmental impacts during the extraction process. It is non-bio degradable in nature & takes 35-42 years to decompose. Thus, management of PET Waste becomes an important social issue. The recycled polyester was gained from PET Waste bottles. The object of research was to study the chemical as well as physical properties of the virgin polyester & Recycled polyester fabric. The Virgin & Recycled polyester yarn with counts of 75D & 150D was procured from Polygenta industries, Nasik & Manjushree industries, Ichalkaranji.
The fabric with EPI 84 & PPI 76 was produced on Sample Weaving Machine. The fabrics dyed with dye, Coralene yellow 4G. The various color aspects like K/S, fastness on polyester & RPET fabric were measured by the computer color matching software.
The results were shown that in physical properties the moisture regains, bending length, and abrasion resistance of recycled polyester is more than virgin polyester. But, tenacity and shrinkage of virgin polyester are more than recycled polyester. In chemical properties, the results of virgin and recycled polyester do not vary much.
Introduction To Virgin and Recycled Polyester
Polyester is made from a non-renewable resource that creates damaging environmental impacts during the extraction process.It is non-bio degradable in nature and takes almost 35 to 42 years to decompose.Thus management of PET waste has become an important social issue.The worldwide consumption of the bottle grade PET was 15 million metric tons which represent almost 8% of total demand
The worldwide consumption of the bottle grade PET was 15 million metric tons which represent almost 8% of the total demand for standard plastic in 2007. The recycled polyester is accounted for 8% overall PET production and it is said to be increasing by 10% every year.
Recycling is the most viable approach to reduce the solid waste. The world’s most recyclable polymer is polyester. Some of the products in which recycled polyester is used as fibers, films, foam, sheeting, food, and non-food contact bottles.It was claimed that in 1994 over 500 million plastic containers were converted over 45 million pounds of polyester fibers for carpet and home furnishing.
This research reviews the method of recycling of the post-consumer waste polyester cycle bottles to form textile fibers. The process involved in complete recycling which consists of a chemical as well as mechanical methods have elaborated the difference in the recycled polyester as compared to the virgin polyester of the same denier is studied which concludes the sustainability of recycled polyester as an alternative to the virgin polyester application in textiles.
The various physical testing like crease recovery angle, bending length, abrasion and single yarn strength tests were analyzed against the existing virgin polyester and the obtained results are discussed for the comparison. The dyeing of the recycled polyester and virgin polyester was carried out with the similar dyeing conditions and same dye and the fastness tests were carried out for analyzing the difference in the dyeing properties.
Materials and methods
1)150 D polyester texturized twist less POY yarn, Polygenta industries, Nasik.
2)75 D polyester texturized twist less POY yarn, procured from Polygenta industries, Nasik.
3)150 D virgin polyester texturized twistless POY yarn, procured from Manjushree industries, Ichalkaranji.
4)75 D virgin polyester texturized twist less POY yarn, procured from Manjushree industries, Ichalkaranji.
Dye colouring yellow 4G 200% manufacturer colortex limited.
CI Index = Disperse yellow 236.
Dispersing agent used = Yogis Perce PA liquid
Weaving of fabric –
The fabric is woven with two different deniers of both recycled as well as virgin polyester texturized yarn with the EPI 84 and PPI 76 on the sample weaving machine. After weaving dyeing is carried out.
Dyeing of polyester –
The dyeing of polyester is carried out with different % shades.
% shade used for experimentation = 0.5,1,2,3.
The dye used = Colarine yellow 4G 200%.
Machine used = MATHIS Labomat. Model No. CH-8156.
Saturation Of Dye On Fabric
The carrier method was used for dyeing and the machine used for dyeing was MATHIS Labomat.
Results & Discussion
- Moisture Regain – The moisture regain of the virgin & recycled polyester fabric was tested by using the oven dry method. It has been tested by the ASTMD2495 standard method.The result shows that the values are not significant; this may be due to the molecular arrangement in recycled polyester by recycling process which does not affect the moisture of recycled polyester. Little change in the moisture regain of both the fibers was observed & moisture regain of recycled polyester was higher than virgin polyester.
- Bending Length:-The bending length for virgin 150denier polyester is more than recycled polyester fabric & same as that for 75denier polyester. This may indicate that the recycled polyester is less stiff as compared to virgin polyester This may be attributed to less crystallinity in recycled polyester. It is tested by stiffness tester & the test method used was ASTMD5732.
- Crease Recovery Angle: – It was tested by crease recovery tester by the ISO4681 method. The crease recovery angle for virgin 150denier is 112of warp & 110.6 of weft. The crease recovery angle for recycled 150denier is 91of warp & 102.4 of weft. This may be due to the cross linked & non linked molecular structure in recycled polyester as compared to virgin polyester, due to this the addition of crease takes place in recycled polyester.
- Abrasion Resistance: – The machine used was Martindale abrasion tester. It was tested byASTMD4157 method. It was seen that recycled sample stand up to 600cycles whereas virgin polyester sample stands up to 400cycles. The abrasion resistance of recycled polyester is more compared to virgin polyester of the same denier. This may be due to the cross linking & not-linear structure of the polyester due to recycling process that resists the abrasion forces.
- Tenacity:-The machine used was Instron Tester with gauge length 50cm. It is tested by the ISO3675 test method.
Recycled polyester 150 denier
Virgin polyester 150 denier
The tenacity of recycled polyester is less as compared to virgin polyester fabric. This may be due to less crystallinity of recycled polyester compared to virgin polyester. The recycled polyester shows less elongation compared to virgin polyester fabric due to an improper arrangement of polymeric chain in recycled yarn.
The coefficient of variation for recycled polyester for elongation is more than virgin polyester for 150D due to the irregular molecular arrangement of cross linked polymeric chain as in case of recycled polyester.
- Shrinkage Test – The boiling water shrinkage test was carried out for both the filaments. It is carried by the ASTMD4974 method.
|Sample||Initial length in cm||Final length in cm||Shrinkage (%)|
|Virgin 75 denier||40.9||37.4||.8.55|
|Recycled 75 denier||40.6||37.5||7.63|
|Virgin 150 denier||40.8||37||9.31|
|Recycled 150 denier||40.4||37.9||6.18|
It was observed that the shrinkage is less in recycled polyester fabric compared to the virgin fabric of the same denier which may be due to molecules which are irregularly arranged & cross linked polymeric structure in case of recycled polyester which resist the shrinkage.
- Tearing strength:-The tearing strength test was carried out on Elmendorf tear tester with the weight range of 6400 on both the fabrics of the same denier of 150. It is carried out by the ASTMD1424 method.
|Average Tearing strength (GMF)|
|Virgin 150 denier||2986.6||3408.6|
|Recycled 150 denier||2858.6||2986.6|
It was seen that decrease in the strength of recycled fabric compared to the virgin fabric of the same denier this may be due to less crystallinity in the recycled sample compared to virgin sample.
- Sublimation Fastness: – The sublimation fastness test was carried out for recycled dyed polyester and virgin dyed polyester on sublimation tester. The test method used was ISO 105-PO1. The sublimation of each fabric was conducted at three different temperatures namely, 170,190, 210 degree Celsius and the time of contact was 45 seconds. The ratings were measured on Macbeth spectrophotometer using colors can with AATCC standard method.
It may be observed that at each temperature the staining scale rating is similar for both recycled as well as virgin polyester samples. This may be due to rearrangement of polymeric chains by recycling process as in case of recycled polyester does not affect the sublimation fastness of recycled polyester dyed with disperse dye.
- Washing Fastness – The washing fastness test was carried out for recycled dyed and virgin dyed polyester fabrics on the Rota Dyer dyeing machine. The washing test method adopted was ISO 105 CO4. The ratings were measured on Macbeth spectrophotometer with the colours can system by AATCC staining method and change in color method.
It can be observed that at different % shades the washing fastness of the recycled polyester fabric sample with respect to virgin polyester sample is not varied much. The rearrangement of polymeric chains by recycling process as in case of recycled polyester does not affect the washing fastness of recycled polyester fabric dyed with disperse dye.
- Rubbing fastness – The rubbing fastness test was carried out for recycled dyed polyester fabric and virgin dyed polyester fabric on the automatic crock meter. The test method used was AATCC 8. The dry, as well as wet rubbing, was tested for both the deniers with 10 cycles. The ratings were measured on Macbeth Spectrophotometer with the colours can system by AATCC staining method.
It may be observed that there is no significant difference seen in the ratings of dry and wet rubbing sample of dyed recycled and dyed virgin polyester fabrics in comparison which concludes the recycling process does not affect the rubbing fastness properties of polyester.
- Light Fastness – The light fastness test was carried out for recycled dyed polyester and virgin dyed polyester fabrics on the light ‘ O ‘ meter machine. The test method used was ASTM D 4303. The dyed fabrics of both the deniers of recycled and virgin polyester were exposed to light for 48 hours. The readings were measured.
It may be seen that there is no significant difference seen in the ratings of dry and wet rubbing sample of dyed recycled polyester fabric and dyed virgin polyester fabric in comparison which concludes that recycling process does not affect the light fastness properties of polyester.
X-RAY Diffraction test (XRD)
Comparison of Crystallinity values tested by XRD test between recycled and virgin polyester samples
|Sample||Crystalline region (%)
|Amorphous region (%)|
From the above table, it can be seen that the crystanallity of the recycled polyester is less as compared to the virgin polyester fabric sample. While the remelting and reformation of the polymer in the recycling process the crystanallity of the recycled polyester yarn may be reduced and the amorphous region may be increased.
Glass Transition Property
The glass transition temperature of the virgin polyester is 75.35 degree Celsius while that of recycled polyester is 87.27 degree Celsius. This may be due to chemical interaction with chemical agencies with the polyester while recycling this is also reflected in dyeing behavior in terms of k/s values and color strength of disperse dyed recycled polyester which is substantially less than those of virgin polyester.
The melting temperature of virgin polyester is 242.72-degree Celsius while that of recycled polyester is 244.15 degrees Celsius. Further, the degradation temperature is 419.99-degree Celsius of virgin polyester while that of recycled polyester is 419.62-degree Celsius, during degradation temperature virgin polyester has 0.7883% and recycled polyester has 10.80% residue. This may be due to the presence of the other ingredients which have carried forward from the recycled process.
The glass transition temperature of the recycled polyester is increased as compared to virgin sample because of the increase in the Tg. The temperature differences from Tg to that of dyeing temperature is reduced which reduces the exhaustion and diffusion of the dye hence, depth of the same shade of recycled sample is less as the virgin polyester sample.
Due to recycling process, the polyester goes to remelting and there is a reformation of molecular chains. There is crosslinking of chains in the fibers so thermal properties of the fibers are affected.
The PET is non-bio degradable in nature, so a global awareness is taken by using the PET Waste bottles for manufacturing textile polyester fibers. Hence, the present scenario aims towards the utilization of PET Waste bottles. The fabric samples were dyed with Coralene yellow 4G 200% dye with shade % 0.5,1,2,3.
The results were shown that in physical properties the moisture regains, bending length, and abrasion resistance of recycled polyester is more than virgin polyester, but tenacity and shrinkage of virgin polyester are more than recycled polyester. In chemical properties, the results of virgin and recycled polyester do not vary much. If this topic is studied further then there will be more scope in the future.
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