DAKRON

Dakron adalah polimer yang tersusun atas glikol dengan asam tereftalat dan terbentuk melalui polimerisasi kondensasi. Dakron banyak dimanfaatkan sebagai bahan sandang.

Dakron merupakan suatu serat polyester. Monomer dakron terbentuk dari etilenglikol dan metiltereftalat.

           

             O                 O

             ll                  ll

                     nH₃CO—C--             --C—OCH₃    +  nHOCH₂ –CH­₂OH   →

                                    metiltereftalat                              etilenglikol

                        

                                  O                        O

                                   ll                   ll

                         ( C--               --CH₂—CH₂O)n    +  nCH₃OH

                                       Dakron                                 methanol

 

 

Dakron termasuk dalam poliester. Dakrom merupakan kopolimer yang terbentuk dari 2 monomer, monomer yang digunakan untuk pembentukan dakron adalah etilen glukol dan dimetil tereftalat. Dakron memiliki struktur yang linier dan tidak ada percabangan. Dakron merupakan polimer termoplastik, polimer termoplastik adalah polimer yang mempunyai sifat tidak tahan terhadap panas. Jika polimer jenis ini dipanaskan, maka akan menjadi lunak dan didinginkan akan mengeras. Beberapa sifat dari polimer termoplastik adalah :

-Berat molekul kecil

 -Tidak tahan terhadap panas

-Jika dipanaskan akan melunak 

-Jika didinginkan akan mengeras

-Mudah untuk diregangkan

-leksibel 

-Titik leleh rendah 

-Dapat dibentuk ulang !daur ulang"

-Mudah larut dalam pelarut yang sesuai

-Memiliki struktur molekul linear atau bercabang. 

 

Dakron merupakan polimer yang dibuat dengan cara kondensasi. Dakron dibuat dengan cara yang sama dengan pembuatan ester, perbedaan adalah pada kedua gugus fungsi yang digunakan dalam pembentukan polimer. Dakron dibuat dari eliten glikol dan dimetil tereftalat dengan memisahkan molekul air  dari alkohol dan dari ester"

Drag Me Down - One Direction

[Harry:]

I've got fire for a heart

I'm not scared of the dark

You've never seen it look so easy

I got a river for a soul 

And baby you're a boat

Baby, you're my only reason

[Louis:]

If I didn't have you there would be nothing left

A shell of a man that could never be his best

If I didn't have you I'd never see the sun

You taught me how to be someone, yeah

[Liam:]

All my life you stood by me 

When no one else was ever behind me

All these lights 

They can't blind me

With your love, nobody can drag me down

[Niall:]

All my life you stood by me 

When no one else was ever behind me

All these lights that can't blind me

With your love, nobody can drag me down

Nobody, nobody

Can drag me down

Nobody, nobody

Can drag me down

[Niall:]

I've got fire for a heart

I'm not scared of the dark

You've never seen it look so easy

I got a river for a soul  

And baby you're a boat

Baby, you're my only reason

[Harry:

If I didn't have you there would be nothing left

A shell of a man that could never be his best

If I didn't have you I'd never see the sun

You taught me how to be someone, yeah

[Niall:]

All my life you stood by me 

When no one else was ever behind me

All these lights that can't blind me

With your love, nobody can drag me down

Nobody, nobody 

Can drag me down

Nobody, nobody

Can drag me down

[Liam:]

All my life you stood by me 

When no one else was ever behind me

All these lights 

They can't blind me

With your love, nobody can drag me down

[Niall:]

All my life you stood by me 

When no one else was ever behind me

All these lights that can't blind me

With your love, nobody can drag me down

(2x)

Nobody, nobody

Can drag me down

Nobody, nobody

Can drag me down

Wiz Khalifa - See You Again

It's been a long day without you my friendAnd I'll tell you all about it when I see you againWe've come a long way from where we beganOh I'll tell you all about it when I see you againWhen I see you again
Damn who knew all the planes we flewGood things we've been throughThat I'll be standing right hereTalking to you about another path IKnow we loved to hit the road and laughBut something told me that it wouldn't lastHad to switch up look at things different see the bigger pictureThose were the days hard work forever pays now I see you in a better place
How could we not talk about family when family's all that we got?Everything I went through you were standing there by my sideAnd now you gonna be with me for the last ride
It's been a long day without you my friendAnd I'll tell you all about it when I see you againWe've come a long way from where we beganOh I'll tell you all about it when I see you againwhen I see you again
First you both go out your wayAnd the vibe is feeling strong and what'sSmall turn to a friendship a friendshipTurn into a bond and that bond will neverBe broke and the love will never get lostAnd when brotherhood come first then the lineWill never be crossed established it on our ownWhen that line had to be drawn and that line is whatWe reach so remember me when I'm gone
How could we not talk about family when family's all that we got?Everything I went through you were standing there by my sideAnd now you gonna be with me for the last ride
So let the light guide your way hold every memoryAs you go and every road you take will always lead you home
It's been a long day without you my friendAnd I'll tell you all about it when I see you againWe've come a long way from where we beganOh I'll tell you all about it when I see you againWhen I see you again

Avril Lavigne - When You're Gone

I always needed time on my ownI never thought I'd need you there when I cryAnd the days feel like years when I'm aloneAnd the bed where you lieis made up on your side
When you walk awayI count the steps that you takeDo you see how much I need you right now?
When you're goneThe pieces of my heart are missing youWhen you're goneThe face I came to know is missing tooWhen you're goneAll the words I need to hear to always get me through the dayAnd make it OKI miss you
I've never felt this way beforeEverything that I doReminds me of youAnd the clothes you leftthey lie on my floorAnd they smell just like youI love the things that you do
When you walk awayI count the steps that you takeDo you see how much I need you right now?
When you're goneThe pieces of my heart are missing youWhen you're goneThe face I came to know is missing tooAnd when you're goneThe words I need to hear to always get me through the dayAnd make it OKI miss you
We were made for each otherOut here foreverI know we wereYeah Yeah
All I ever wanted was for you to knowEverything I do I give my heart and soulI can hardly breathe, I need to feel you here with meYeah
When you're goneThe pieces of my heart are missing youWhen you're goneThe face I came to know is missing tooWhen you're goneThe words I need to hear will always get me through the dayAnd make it OKI miss you

Aplikasi Larutan Penyangga Dalam Analisis Kimia

Larutan penyangga sangat penting dalam kehidupan; misalnya dalam analisis kimia, biokimia, bakteriologi, zat warna, fotografi, dan industri kulit. Dalam bidang biokimia, kultur jaringan dan bakteri mengalami proses yang sangat sensitif terhadap perubahan pH. Darah dalam tubuh manusia mempunyai kisaran pH 7,35 sampai 7,45, dan apabila pH darah manusia di atas 7,8 akan menyebabkan organ tubuh manusia dapat rusak, sehingga harus dijaga kisaran pHnya dengan larutan penyangga.

Larutan buffer diperlukan untuk menjaga pH yang tepat untuk enzim dalam banyak organisme untuk bekerja. Banyak enzim bekerja hanya pada kondisi sangat tepat; bila pH bergerak ke luar dari rentang yang sempit, maka kerja enzim melambat atau bahkan berhenti dan dapat mengalami denaturasi atau kehilangan sifat alaminya. Dalam banyak kasus denaturasi dapat melumpuh-kan aktivitas katalitiknya secara permanen. Buffer asam karbonat (H₂CO₃) dan bikarbonat (HCO₃⁻) terdapat dalam plasma darah, untuk mempertahankan pH antara 7,35 dan 7,45.

Secara industri, larutan buffer digunakan dalam proses fermentasi dan dalam pengaturan kondisi yang tepat untuk bahan pewarna yang digunakan di pabrik pewarnaan. Larutan buffer juga digunakan dalam analisis kimia dan kalibrasi pH meter. Mayoritas sampel biologi yang digunakan dalam riset dibuat dengan buffer, terutama air asin yang dibufferkan dengan fosfat (PBS) pada pH 7,4.

1. Darah Sebagai Larutan Penyangga

Ada beberapa faktor yang terlibat dalam pengendalian pH darah, diantaranya penyangga karbonat, penyangga hemoglobin dan penyangga fosfat.

a. Penyangga Karbonat

Penyangga karbonat berasal dari campuran asam karbonat (H ₂ CO ₃ ) dengan basa konjugasi bikarbonat (HCO ₃ ).
H ₂ CO _{3 (aq)} –> HCO _3(aq) + H ⁺ _(aq)
Penyangga karbonat sangat berperan penting dalam mengontrol pH darah. Pelari maraton dapat mengalami kondisi asidosis, yaitu penurunan pH darah yang disebabkan oleh metabolisme yang tinggi sehingga meningkatkan produksi ion bikarbonat. Kondisi asidosis ini dapat mengakibatkan penyakit jantung, ginjal, diabetes miletus (penyakit gula) dan diare. Orang yang mendaki gunung tanpa oksigen tambahan dapat menderita alkalosis, yaitu peningkatan pH darah. Kadar oksigen yang sedikit di gunung dapat membuat para pendaki bernafas lebih cepat, sehingga gas karbondioksida yang dilepas terlalu banyak, padahal CO ₂ dapat larut dalam air menghasilkan H ₂ CO ₃ . Hal ini mengakibatkan pH darah akan naik. Kondisi alkalosis dapat mengakibatkan hiperventilasi (bernafas terlalu berlebihan, kadang-kadang karena cemas dan histeris).

b. Penyangga Hemoglobin

Pada darah, terdapat hemoglobin yang dapat mengikat oksigen untuk selanjutnya dibawa ke seluruh sel tubuh. Reaksi kesetimbangan dari larutan penyangga oksi hemoglobin adalah:
HHb + O _{2 (g)} « HbO ₂ ^- + H ⁺
Asam hemoglobin ion aksi hemoglobin
Keberadaan oksigen pada reaksi di atas dapat memengaruhi konsentrasi ion H ⁺, sehingga pH darah juga dipengaruhi olehnya. Pada reaksi di atas O ₂ bersifat basa. Hemoglobin yang telah melepaskan O ₂ dapat mengikat H ⁺ dan membentuk asam hemoglobin. Sehingga ion H ⁺ yang dilepaskan pada peruraian H ₂ CO ₃ merupakan asam yang diproduksi oleh CO ₂ yang terlarut dalam air saat metabolisme.
 
c. Penyangga Fosfat

Pada cairan intra sel, kehadiran penyangga fosfat sangat penting dalam mengatur pH darah. Penyangga ini berasal dari campuran dihidrogen fosfat (H ₂ PO ₄ ^- ) dengan monohidrogen fosfat (HPO ₃ ^2- ).
H ₂ PO ₄ ^- _(aq) + H ⁺ _(aq) –> H ₂ PO _4(aq)
H ₂ PO ₄ – _(aq) + OH ^- _(aq) –> HPO ₄ ^2- _(aq) ) + H ₂ O _(aq)
Penyangga fosfat dapat mempertahankan pH darah 7,4. Penyangga di luar sel hanya sedikit jumlahnya, tetapi sangat penting untuk larutan penyangga urin.


2. Air Ludah sebagai Larutan Penyangga
Gigi dapat larut jika dimasukkan pada larutan asam yang kuat. Email gigi yang rusak dapat menyebabkan kuman masuk ke dalam gigi. Air ludah dapat mempertahankan pH pada mulut sekitar 6,8. Air liur mengandung larutan penyangga fosfat yang dapat menetralisir asam yang terbentuk dari fermentasi sisa-sisa makanan.


3. Menjaga keseimbangan pH tanaman.
Suatu metode penanaman dengan media selain tanah, biasanya ikerjakan dalam kamar kaca dengan menggunakan mendium air yang berisi zat hara, disebut dengan hidroponik . Setiap tanaman memiliki pH tertentu agar dapat tumbuh dengan baik. Oleh karena itu dibutuhkan larutan penyangga agar pH dapat dijaga.


4. Larutan Penyangga pada Obat-Obatan
Asam asetilsalisilat merupakan komponen utama dari tablet aspirin, merupakan obat penghilang rasa nyeri. Adanya asam pada aspirin dapat menyebabkan perubahan pH pada perut. Perubahan pH ini mengakibakan pembentukan hormon, untuk merangsang penggumpalan darah, terhambat; sehingga pendarahan tidak dapat dihindarkan. Oleh karena itu, pada aspirin ditambahkan MgO yang dapat mentransfer kelebihan asam.

One Direction - Night Changes

Going out tonight
Changes into something red
Her mother doesn’t like that kind of dress
Everything she never had, she’s showing off
 

Driving too fast
Moon is breaking through her hair
She’s heading for something that she won’t forget
Having no regrets is all that she really wants

 

We’re getting only older baby
And I’ve been thinking about it lately
Does it ever drive you crazy
Just how fast the night changes?
Everything that you’ve ever dreamed of
Disappearing when you wake up
But there’s nothing to be afraid of
Even when the night changes
It will never change me and you

 

Chasing it tonight

Doubts are running around her head

He’s waiting, hides behind a cigarette

Heart is beating loud and she doesn’t want it to stop

 

Moving too fast

Moon is lighting up her skin

She’s falling, doesn’t even know it yet

Having no regrets is all that she really wants

We’re getting only older baby
And I’ve been thinking about it lately
Does it ever drive you crazy
Just how fast the night changes?
Everything that you’ve ever dreamed of
Disappearing when you wake up
But there’s nothing to be afraid of
Even when the night changes
It will never change me and you

Going out tonight
Changes into something red
Her mother doesn’t like that kind of dress
Reminds her of the missing piece of innocence she lost

We’re getting only older baby
And I’ve been thinking about it lately
Does it ever drive you crazy
Just how fast the night changes?
Everything that you’ve ever dreamed of
Disappearing when you wake up
But there’s nothing to be afraid of
Even when the night changes
It will never change me and you

 

 

It will never change, baby
It will never change, baby
It will never change me and you

Steal My Girl - One Direction

She's been my queen since we were sixteen
We want the same things, we dream the same dreams, alright
(Alright)

I got it all 'cause she is the one
Her mum calls me 'love', her dad calls me 'son', alright
(Alright)

I know, I know, I know for sure

Everybody wanna steal my girl
Everybody wanna take her heart away
Couple billion in the whole wide world
Find another one 'cause she belongs to me

Everybody wanna steal my girl

Everybody wanna take her heart away

Couple billion in the whole wide world

Find another one 'cause she belongs to me

Na na na na na na (oh, yeah)

Na na na na na na (alright)
Na na na na na na
Na na

She belongs to me

Kisses like cream, her walk is so mean
And every jaw drops when she's in those jeans, alright
(Alright)

I don't exist if I don't have her
The sun doesn't shine, the world doesn't turn, alright
(Alright)

But I know, I know, I know for sure

Everybody wanna steal my girl
Everybody wanna take her heart away
Couple billion in the whole wide world
Find another one 'cause she belongs to me

Everybody wanna steal my girl
Everybody wanna take her heart away
Couple billion in the whole wide world
Find another one 'cause she belongs to me

Na na na na na na (Oh, yeah)
Na na na na na na (Alright)
Na na na na na na
Na na na na na na

She knows, she knows
That I never let her down before

She knows, she knows

That I'm never gonna let another take her love from me now

Everybody wants to steal my girl
Everybody wants to take her love away
Couple billion in the whole wide world
Well, find another one 'cause she belongs to me

Everybody wanna steal my girl
Everybody wanna take her heart away
Couple billion in the whole wide world
Find another one 'cause she belongs to me

Na na na na na na (Oh, yeah, alright, yeah)
Na na na na na na (Alright)
Na na na na na na
Na na

She belongs to me

Na na na na na na (Oh, yeah) (She belongs to me, yeah)
Na na na na na na (Alright)
Na na na na na na

She belongs to me